Enhanced degradation of ciprofloxacin by graphitized mesoporous carbon (GMC)-TiO2 nanocomposite: Strong synergy of adsorption-photocatalysis and antibiotics degradation mechanism

Removal of mixed pollutants of perfluorooctanoic acid and 2,4,6-trichlorophenol via adsorption-photocatalysis using Ga2O3-Bi4O7 combining with fluorine-doped covalent triazine framework: Role of different active species

Perfluorooctanoic acid (PFOA) and 2,4,6-trichlorophenol (2,4,6-TCP) are significant pollutants found in textile wastewater, posing severe threats to ecological environments. The construction of an adsorption-photocatalytic system enables the efficient removal of mixed pollutants by harnessing their synergistic effect, thereby overcoming the limitations of removing mixed pollutants with single water treatment technologies. Herein, fluorine-doped covalent triazine framework (F-CTF) was combined with Ga2O3-Bi4O7 heterojunction to obtain Ga2O3-Bi4O7/F-CTF (GaBi/CTF). F-CTF greatly facilitates the adsorption process and provides convenience for photocatalysis. Simultaneously, the excellent conductivity of F-CTF promoted the separation of photoinduced charge carriers in Ga2O3-Bi4O7. GaBi/CTF5 (5 is the mass percentage of F-CTF) showed excellent degradation performance, and the removal rates of PFOA and 2,4,6-TCP reached 93.0 % and 100.0 % within 90 min, respectively. Mechanistic analysis revealed that 2,4,6-TCP and PFOA were attacked by distinct active species because of the disparate characteristics. The presence of phenolic hydroxyl groups makes 2,4,6-TCP more vulnerable to superoxide radicals (·O2-) and hydroxyl radicals (·OH), whereas PFOA is oxidized by holes (h+). The coexistence of mixed pollutants with diverse characteristics enables optimal utilization of active species generated within photocatalytic system. Moreover, the good stability of GaBi/CTF5 provides a feasible solution for efficient treatment of mixed pollutants in textile wastewater.

Fluoroquinolone antibiotics in the aquatic environment: environmental distribution, the research status and eco-toxicity

The increasing presence of fluoroquinolone (FQ) antibiotics in aquatic environments is a growing concern due to their widespread use, negatively impacting aquatic organisms. This paper provides an overview of the environmental distribution, sources, fate, and both single and mixed toxicity of FQ antibiotics in aquatic environments. It also examines the accumulation of FQ antibiotics in aquatic organisms and their transfer into the human body through the food chain. The study identifies critical factors such as metabolism characteristics, physiochemical characteristics, light, temperature, dissolved oxygen, and environmental compatibility that influence the presence of FQ antibiotics in aquatic environments. Mixed pollutants of FQ antibiotics pose significant risks to the ecological environment. Additionally, the paper critically discusses advanced treatment technologies designed to remove FQ antibiotics from wastewater, focusing on advanced oxidation processes (AOPs) and electrochemical advanced oxidation processes (EAOPs). The discussion also includes the benefits and limitations of these technologies in degrading FQ antibiotics in wastewater treatment plants. The paper concludes by proposing new approaches for regulating and controlling FQ antibiotics to aid in the development of ecological protection measures.

Effluent toxicity study using biomarkers for ciprofloxacin photoelectrocatalytic degradation by bismuth-doped titanium dioxide nanotubes

Ciprofloxacin hydrochloride (CIP) is a broad-spectrum synthetic antibiotic often found in domestic sewage and industrial waste due to the inefficiency of conventional treatments. Given the potential risk of drug accumulation, this study presents coatings of titanium dioxide nanotubes (TiO2) doped with different bismuth (Bi) concentrations to degrade CIP through photocatalytic and photoelectrochemical processes. Characterization studies revealed that bismuth (Bi) doping affected the morphology of the materials, with concentrations of 0.01 and 0.05 mol L-1, resulting in collapsed materials with a smaller active surface area. Photocatalysis tests for all the materials exhibited a similar degree of efficiency to photolysis, approximately 33%. Ecotoxicity tests using the biomarkers Lactuca sativa L., Lemna minor, and Artemia salina indicated that, although they were similar to photolysis in terms of efficiency, the effluents generated when employing the doped catalysts showed lower levels of toxicity, with the best results achieved for the material doped with 0.005 mol L-1 of Bi, with a toxicity level approximately 40% lower. Photoelectrocatalysis proved to be the most efficient CIP degradation technique. The highest degradation rate was observed for materials doped with 0.005 mol L-1 of Bi, with an efficiency of 46%, which is 1.4 times more efficient than photolysis. These results demonstrate that materials doped with low amounts of Bi can be effectively used as photoanodes for drug degradation, as their performance is superior, and the final product generated exhibits low toxicity to living organisms.

Insight into typical photo-assisted AOPs for the degradation of antibiotic micropollutants: Mechanisms and research gaps

Due to the incomplete elimination by traditional wastewater treatment, antibiotics are becoming emerging contaminants, which are proved to be ubiquitous and promote bacterial resistance in the aquatic systems. Antibiotic pollution has raised particular concerns, calling for improved methods to clean wastewater and water. Photo-assisted advanced oxidation processes (AOPs) have attracted increasing attention because of the fast reaction rate, high oxidation capacity and low selectivity to remove antibiotics from wastewater. On the basis of latest literature, we found some new breakthroughs in the degradation mechanisms of antibiotic micropollutants with respect to the AOPs. Therefore, this paper summarizes and highlights the degradation kinetics, pathways and mechanisms of antibiotics degraded by the photo-assisted AOPs, including the UV/O3 process, photo-Fenton technology, and photocatalysis. In the processes, functional groups are attacked by hydroxyl radicals, and major structures are destroyed subsequently, which depends on the classes of antibiotics. Meanwhile, their basic principles, current applications and influencing factors are briefly discussed. The main challenges, prospects, and recommendations for the improvement of photo-assisted AOPs are proposed to better remove antibiotics from wastewater.

Electrostatic Self-Assembled Synthesis of Amorphous/Crystalline g-C3N4 Homo-Junction for Efficient Photocatalytic H2 Production with Simultaneous Antibiotic Degradation

g-C3N4 has been regarded as a promising photocatalyst for photo-reforming antibiotics for H2 production but still suffers from its high charge recombination, which has been proven to be solvable by constructing a g-C3N4 homo-junction. However, those reported methods based on uncontrollable calcination for preparing a g-C3N4 homo-junction are difficult to reproduce. Herein, an amorphous/crystalline g-C3N4 homo-junction (ACN/CCN) was successfully synthesized via the electrostatic self-assembly attachment of negatively charged crystalline g-C3N4 nanorods (CCN) on positively charged amorphous g-C3N4 sheets (ACN). All the ACN/CCN samples displayed much higher photo-reforming of antibiotics for H2 production ability than that of pristine ACN and CCN. In particular, ACN/CCN-2 with the optimal ratio exhibited the best photocatalytic performance, with a H2 evolution rate of 162.5 μmol·g-1·h-1 and simultaneous consecutive ciprofloxacin (CIP) degradation under light irradiation for 4 h. The UV-vis diffuse reflectance spectra (DRS), photoluminescence (PL), and electrochemical results revealed that a homo-junction is formed in ACN/CCN due to the difference in the band arrangement of ACN and CCN, which effectively suppressed the charge recombination and then led to those above significantly enhanced photocatalytic activity. Moreover, H2 was generated from the water reduction reaction with a photogenerated electron (e-), and CIP was degraded via a photogenerated hole (h+). ACN/CCN exhibited adequate photostability and reusability for photocatalytic H2 production with simultaneous CIP degradation. This work provides a new idea for rationally designing and preparing homo-junction photocatalysts to achieve the dual purpose of chemical energy production and environmental treatment.

Facile aqueous synthesis and comparative evaluation of TiO2-semiconductor and TiO2-metal nanohybrid photocatalysts in antibiotics degradation under visible light

Advanced oxidation processes using TiO2-based nanomaterials are sustainable technologies that hold great promise for the degradation of many types of pollutants including pharmaceutical residues. A wide variety of heterostructures coupling TiO2 with visible-light active nanomaterials have been explored to shift its photocatalytic properties to harness sun irradiation but a systematic comparison between them is lacking in the current literature. Furthermore, the high number of proposed nanostructures with different size, morphology, and surface area, and the often complex synthesis processes hamper the transition of these materials into commercial and effective solutions for environmental remediation. Herein, we have designed a facile and cost-effective method to synthesize two heterostructured photocatalysts representative of two main families of novel structures proposed, hybrids of TiO2 with metal (Au) and semiconductor (CeO2) nanomaterials. The photocatalysts have been extensively characterized to ensure a good comparability in terms of co-catalyst doping characteristics, morphology and surface area. The photocatalytic degradation of ciprofloxacin and sulfamethoxazole as target pollutants, two antibiotics of high concern polluting water sources, has been evaluated and CeO2/TiO2 exhibited the highest activity, achieving complete antibiotic degradation at very low photocatalyst concentrations. Our study provides new insights into the development of inexpensive heterostructured photocatalysts and suggests that the non-stoichiometry and characteristic d and f electronic orbital configuration of CeO2 have a significantly improved role in the enhancement of the photocatalytic reaction.

Multi-antibiotics removal under UV-A light using sol-gel prepared TiO2: Central composite design, effect of persulfate addition and degradation pathway study

The removal of three antibiotics i.e., metronidazole (MNZ), ciprofloxacin (CIP) and tetracycline (TET), from aqueous system via TiO2 photocatalysis under UV-A light was investigated. Photocatalyst(s) were prepared using sol-gel method under different calcination temperatures (400-800 °C) and water-alcohol ratio. The spherical shaped catalyst (mean particle size ∼ 61 nm) was characterized via FTIR, XRD, BET, SEM, Raman, XPS, UV-DRS, and Fluorometry, and point of zero charge was also determined (pHPZC ∼ 6.6). Batch photo-catalytic degradation studies have shown complete degradation of MNZ, CIP and TET after 50, 75 and 20 min with a TOC removal of 37%, 44% and 31%, respectively. The activity of sol-gel prepared TiO2 was comparatively higher than commercially available pure anatase TiO2 nanoparticles due to lesser mean particle size. The ratio of water to alcohol in the preparation of TiO2 catalyst was found to have significant effect on antibiotic removal. Moreover, persulfate (PS) addition of 0.1 g/L amplified the pseudo-first-order removal-rate constant by 2.75, 3.3 and 1.6 times for MNZ, CIP and TET, respectively. The higher initial pH values (8 and 10) have shown the best removal efficiency for all antibiotics. Subsequently, central composite design (CCD) experiments were conducted under multi-antibiotic conditions. Near complete removal of all antibiotics were observed within 120 min. Scavenging studies revealed that hydroxyl and superoxide radicals play major roles in photo-catalytic degradation of MNZ, CIP and TET. During photocatalysis, MNZ degradation was initiated by hydroxylation reaction, CIP by piperazine ring opening by hydroxyl attack and TET by multiple hydroxylation process. Overall, TiO2 showed good efficiency at degrading multiple antibiotics and has the potential for practical application on a larger scale.

In Silico Guided Design of Metal/Semiconductor Photocatalysts: A Case of Cu-Modified TiO2 for Ciprofloxacin Degradation

(1) Background: An increasing use of pharmaceutics imposes a need for the permanent development of efficient strategies, including the tailoring of highly specific new materials for their removal from the environment. Photocatalytic degradation has been the subject of increasing interest of the researchers in the field. (2) Methods: This paper is focused on the investigation of the possibility to deposit a thin metal layer on a TiO2 surface and study its photocatalytic performance for the degradation of ciprofloxacin using a combination of theoretical and experimental methods. (3) Results: Based on the extensive DFT screening of 24 d-metals' adhesion on TiO2, Cu was selected for further work, due to the satisfactory expected stability and good availability. The (Cu)TiO2 was successfully synthesized and characterized with XRD, SEM+EDS and UV-Vis spectrophotometry. The uniformly distributed copper on the TiO2 surface corresponds to the binding on high-affinity oxygen-rich sites, as proposed with DFT calculations. The photocatalytic degradation rate of ciprofloxacin was improved by about a factor of 1.5 compared to the bare non-modified TiO2. (4) Conclusions: The observed result was ascribed to the ability of adsorbed Cu to impede the agglomeration of TiO2 and increase the active catalytic area, and bandgap narrowing predicted with DFT calculations.

Simultaneous removal of pharmaceuticals and heavy metals from aqueous phase via adsorptive strategy: A critical review

The coexistence of pharmaceuticals and heavy metals is regarded as a serious threat to aquatic environments. Adsorbents have been widely applied to the simultaneous removal of pharmaceuticals and metals from aqueous phase. Through a comprehensive review, behaviors that promote, inhibit, or have no effect on simultaneous adsorption of pharmaceuticals and heavy metals were found to depend on the system of contaminants and adsorbents and their environmental conditions, such as: characteristics of adsorbent and pollutant, temperature, pH, inorganic ions, and natural organic matter. Bridging and competition effects are the main reasons for promoting and inhibiting adsorption in coexisting systems, respectively. The promotion is more significant in neutral or alkaline conditions. After simultaneous adsorption, a solvent elution approach was most commonly used for regeneration of saturated adsorbents. To conclude, this work could help to sort out the theoretical knowledge in this field, and may provide new insights into the prevention and control of pharmaceuticals and heavy metals coexisting in wastewater.

Eliminating ciprofloxacin antibiotic contamination from water with a novel submerged thermal plasma technology

Thermal plasma is successfully used to degrade the model pharmaceutical wastewater ciprofloxacin (CIP) under submerged operating conditions at atmospheric pressure. The model aqueous solution is prepared for two different concentrations (10 and 25 mg/L) and treated separately at 7 kW discharge power with two different plasma-forming gas compositions, Ar/Air and Ar/CO₂. A direct current (DC) hollow cathode plasma torch produces a thermal plasma jet inside the solution. The effect of plasma gas compositions on the CIP degradation process is investigated, and the corresponding degradation and mineralisation efficiencies for different treatment times are systematically compared using high-performance liquid chromatography (HPLC) and total organic carbon (TOC) analysis, respectively. Submerged Ar/CO₂ plasma shows higher degradation and mineralisation efficiency than the Ar/Air plasma. Energy yields of 74.32 mg/kWh and 176.98 mg/kWh are achieved for a 5-min treatment by Ar/CO₂ submerged thermal plasma at concentrations of 10 mg/L and 25 mg/L, respectively. The degradation of CIP by submerged plasma shows a resemblance with first-order reaction kinetics having reaction rates 0.149 min^-1 and 0.073 min^-1 for Ar/CO₂ and Ar/Air, respectively. Density Functional Theory (DFT) calculations are used to identify the various reactive sites on CIP, and the results are consistent with the formation of various intermediates detected through liquid chromatography-mass spectrometry (LC-MS) analysis. These findings suggest that reactive species formed through thermal and photochemical processes in submerged thermal plasma play a significant role in the degradation of CIP. This study also offers a possible way of using CO₂ gas in wastewater treatment using submerged thermal plasma.

Antibiotics oxytetracycline removal by photocatalyst titanium dioxide and graphitic carbon nitride in aquaculture wastewater

The surge in the use of antibiotics, especially in aquaculture, has led to development of antibiotic resistance genes, which will harm environmental and public health. One of the most commonly used antibiotics in aquaculture is oxytetracycline (OTC). Employing photocatalysis, this study compared OTC degradation efficiency of two different types of common photocatalysts, TiO₂ and graphitic carbon nitride (GCN) in terms of their photochemical properties and underlying photocatalytic mechanism. For reference purpose, self-synthesized GCN from urea precursor (GCN-Urea) and commercial GCN (GCN-Commercial) were both examined. OTC adsorption-photocatalysis removal rates in pure OTC solution by TiO₂, GCN-Urea and GCN-Commercial were attained at 95%, 60% and 40% respectively. Photochemical properties evaluated included light absorption, band gap, valence and conduction band positions, photoluminescence, cyclic voltammetry, BET surface area and adsorption capability of the photocatalysts. Through the evaluations, this study provides novel insights towards current state-of-the-art heterogeneous photocatalytic processes. The electron-hole recombination examined by photoluminescence is not the key factor influencing the photocatalytic efficacies as commonly discussed. On the contrary, the dominating factors governing the higher OTC degradation efficiency of TiO₂ compared to GCN are the high mobility of electrons that leads to high redox capability and the high pollutant-photocatalyst affinity. These claims are proven by 86% and 40% more intense anodic and cathodic cyclic voltammetry curve peaks of TiO₂ as compared to both GCNs. OTC also demonstrated 1.7 and 2.3 times higher affinity towards TiO₂ than GCN-Urea and GCN-Commercial. OTC removal by TiO₂ in real aquaculture wastewater only achieved 50%, due to significant inhibition effect by dissolved solids, dissolved organic matters and high ionic contents in the wastewater.

Repeated fluctuation of Cu2+ concentration during photocatalytic purification of SMZ-Cu2+ combined pollution: Behavior, mechanism and application

Although the effect of Cu²⁺ on antibiotic removal during photocatalytic reaction has been studied in depth, there is less known about the effect of antibiotics on Cu²⁺ removal. In this study, we report for the first time that, during the photocatalytic purification of sulfamerazine (SMZ) and Cu²⁺ combined pollution, Cu²⁺ concentration showed an obvious five-stage fluctuation, which was completely different from the simple promotion or inhibition reported in previous studies. By employing HPLC-MS analysis and density functional theory (DFT) calculation, the repeated fluctuation of Cu²⁺ concentration was found to be closely related to the SMZ degradation process, mainly resulting from solution pH drop and formation of Cu-containing intermediates which acted as sacrificial agents for Cu²⁺ reduction. In addition, compared with the SMZ-free system, the presence of SMZ can greatly enhance the deep removal of Cu²⁺ (minimum Cu²⁺ concentration was only 0.17 mg/L vs. 1.28 mg/L without SMZ), and there was a wide time interval to ensure the efficient recovery of Cu metal. More interestingly, the in-situ obtained Cu-decorated TiO₂ photocatalyst performed well in water splitting, nitrogen fixation and bacterial sterilization. Results of this study confirmed the great potential of photocatalytic technology in purifying antibiotic-heavy metal combined pollution.

Synergetic effect of adsorption and photocatalysis by zinc ferrite-anchored graphitic carbon nitride nanosheet for the removal of ciprofloxacin under visible light irradiation

Ciprofloxacin (CIP) belongs to the fluoroquinolone antibiotic family. It is mostly used for the treatment of bacterial infections and highly recalcitrant to naturally decompose. The nanocomposite was successfully constructed by zinc ferrite nanoparticle anchored onto graphitic carbon nitride nanosheet (ZFNP–CNNS). The structural, morphological, and optical properties of the ZFNP–CNNS nanocomposite were investigated. Moreover, the enhanced photocatalytic performance of the ZFNP–CNNS nanocomposite was a result of the synergetic effect between adsorption and photocatalysis. The adsorption study showed that the ZFNP–CNNS nanocomposite has heterogeneous active sites with multilayers and the maximum CIP adsorption capacity was 15.49 mg g−1. However, the photodegradation efficacy of CIP reached up to five times compared to that of pristine CNNS. The high adsorption–photocatalytic synergetic effect of the ZFNP–CNNS nanocomposite has great application in wastewater treatment.

Effect of metal doping (Me = Zn, Cu, Co, Mn) on the performance of bismuth ferrite as peroxymonosulfate activator for ciprofloxacin removal

In this study, a facile hydrothermal method was employed to prepare Me-doped Bi₂Fe₄O₉ (Me = Zn, Cu, Co, and Mn) as peroxymonosulfate (PMS) activator for ciprofloxacin (CIP) degradation. The characteristics of the Me-doped bismuth ferrites were investigated using various characterization instruments including SEM, TEM, FTIR and porosimeter indicating that the Me-doped Bi₂Fe₄O₉ with nanosheet-like square orthorhombic structure was successfully obtained. The catalytic activity of various Me-doped Bi₂Fe₄O₉ was compared and the results indicated that the Cu-doped Bi₂Fe₄O₉ at 0.08 wt.% (denoted as BFCuO-0.08) possessed the greatest catalytic activity (k_app = 0.085 min^-1) over other Me-doped Bi₂Fe₄O₉ under the same condition. The synergistic interaction between Cu, Fe and oxygen vacancies are the key factors which enhanced the performance of Me-doped Bi₂Fe₄O₉. The effects of catalyst loading, PMS dosage, and pH on CIP degradation were also investigated indicating that the performance increased with increasing catalyst loading, PMS dosage, and pH. Meanwhile, the dominant reactive oxygen species was identified using the chemical scavengers with SO₄^•-, ^•OH, and ¹O₂ playing a major role in CIP degradation. The performance of BFCuO-0.08 deteriorated in real water matrix (tap water, river water and secondary effluent) due to the presence of various water matrix species. Nevertheless, the BFCuO-0.08 catalyst possessed remarkable stability and can be reused for at least four successive cycles with >70% of CIP degradation efficiency indicating that it is a promising catalyst for antibiotics removal.

Insight into advanced oxidation processes for the degradation of fluoroquinolone antibiotics: Removal, mechanism, and influencing factors

The enrichment and transport of antibiotics in the environments pose many potential hazards to aquatic animals and humans, which has become one of the public health challenges worldwide. As a widely used class of antibiotics, fluoroquinolones (FQs) generally accumulated in the environments as traditional sewage treatment plants cannot completely remove them. Advanced oxidation processes (AOPs) have been shown to be a promising method for the abatement of antibiotic contamination. In this review, influencing factors and relevant mechanisms of FQs removal by various AOPs were summarized. Compared with other AOPs, photocatalytic ozone may be considered as a cost-effective method for degrading FQs. Finally, the benefits and application restrictions of AOPs were discussed, along with proposed research directions to provide new insights into the control of FQs pollutant via AOPs in practical applications.

Chlorophyll sensitized and salicylic acid functionalized TiO2 nanoparticles as a stable and efficient catalyst for the photocatalytic degradation of ciprofloxacin with visible light

Developing efficient and stable visible light active photocatalyst has significant environmental applications. Though dye sensitization of TiO₂ nanoparticles with natural chlorophyll pigments can potentially impart visible light activity, their long-term stability is a major concern. We investigated the functionalization of TiO₂ with salicylic acid, and subsequent sensitization with chlorophylls to improve the catalyst stability for the photocatalytic degradation of Ciprofloxacin (CPX) under visible light. A significant improvement in the degradation efficiency and catalyst stability was observed for five reuse cycles. Further, an optimum CPX degradation of ∼75% was achieved with 0.75 g L^-1 catalyst dosage of 0.1 chl/0.1 SA-TiO₂, initial pH of 6, and 10 ppm of initial CPX for a visible light exposure of 2 h. The degradation followed the pseudo-second-order kinetics. In addition, the ciprofloxacin degradation was reduced in the wastewater matrix system due to the presence of other scavenging species such as chlorides, sulphates, and alkalinity. Significant reduction in the toxicity of degradation compounds after the photocatalytic degradation was observed in comparison to parent CPX. Further, the degradation pathway and plausible mechanism of degradation of CPX were also proposed.

Photocatalytic Degradation of Ciprofloxacin by UV Light Using N-Doped TiO2 in Suspension and Coated Forms

The presence of organic compounds such as ciprofloxacin in untreated pharmaceutical wastewater often poses a serious health risk to human and aquatic life when discharged into water bodies. One of the most effective means of removing ciprofloxacin from wastewater is photocatalytic degradation. However, the synthesis of an effective photocatalyst that can degrade the organic pollutant in the wastewater is often a challenge. Hence, this study focuses on the synthesis and application of nitrogen-doped TiO2 (N-TiO2) in suspension and coated forms for the photocatalytic degradation of ciprofloxacin in wastewater by applying UV-light irradiation. The nitrogen-doped TiO2 photocatalyst was prepared by a co-precipitation process and characterized using energy-dispersive X-ray spectroscopy, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The effects of the initial concentration of the ciprofloxacin (6, 12, 18, or 30 ppm), pH (3, 5, 7, or 9), and flow rate (0.4, 0.8, 0.95, or 1.5 L/min) on the degradation of the ciprofloxacin over the N-TiO2 were investigated. The results showed that the removal efficiency of ciprofloxacin was enhanced by increasing the initial ciprofloxacin concentration, while it was decreased with the increase in the feed flow rate. The best operating conditions were obtained using an initial ciprofloxacin concentration of 30 ppm, pH of 5, and feed flow rate of 0.4 L/min. Under these operating conditions, removal efficiencies of 87.87% and 93.6% were obtained for net TiO2 and N-TiO2 of 5 wt% in suspension form, respectively, while 94.5% ciprofloxacin removal efficiency was obtained using coated 5 wt% N-TiO2 after 2 h of photocatalytic degradation. Based on the response surface optimization strategy, a quadratic model was suggested to obtain mathematical expressions to predict the ciprofloxacin removal efficiency under various studied operational parameters.

Pharmaceutical residues: One of the significant problems in achieving 'clean water for all' and its solution

With the rapid emergence of various metabolic and multiple-drug-resistant infectious diseases, new pharmaceuticals are continuously being introduced in the market. The excess production and use of pharmaceuticals and their untreated/unmetabolized release in the environment cause the contamination of aquatic ecosystem, and thus, compromise the environment and human-health. The present review provides insights into the classification, sources, occurrence, harmful impacts, and existing technologies to curb these problems. A comprehensive detail of various biological and nanotechnological strategies for the removal of pharmaceutical residues from water is critically discussed focusing on their efficiencies, and current limitations to design improved-technologies for their lab-to-field applications. Furthermore, the review highlights and suggests the scope of integrated bionanotechnological methods for enhanced removal of pharmaceutical residues from water to fulfill the United Nations Sustainable Development Goal (UN-SDG) for providing clean potable water for all.

Adsorption behaviors of three antibiotics in single and co-existing aqueous solutions using mesoporous carbon

The residual antibiotics detected frequently in aquatic environment may pose a potential threat to human health and ecosystem. Exploring a possible way to remove them from antibiotic polluted-water is a key problem demanding prompt solution. To investigate their adsorption characteristics, three antibiotics including tetracycline (TC), ciprofloxacin (CIP), and sulfadiazine (SDZ) have been removed using sucrose-based mesoporous carbon (SMC) in single and co-existing systems. Characterization revealed that the SMC had a high Brunauer-Emmett-Teller (BET) surface area (1215.48 m²/g), large mesoporous pore size (6.36 nm), and abundant oxygen-containing functional groups, which might offer sufficient adsorption sites for antibiotics. The process of antibiotics adsorption was described well using pseudo-second-order model. The rate constant K₂ at various temperatures followed the order 308 K > 298 K > 288 K. This finding suggesting the increase in temperature could promote the removal of antibiotics. The maximum adsorption capacities for TC (232.10 mg/g), CIP (257.30 mg/g), and SDZ (204.28 mg/g) of SMC were obtained using Langmuir isotherm (pH = 4-6, T = 308K, SMC dosage = 10 mg, C₀ = 30-40 mg/L). These data implied SMC had the excellent adsorptive property and affinity to antibiotics. In binary systems, SMC offers efficient removal percentages (>90%) for each of the target antibiotic. While the removal efficiencies of TC, CIP, and SDZ by SMC in the ternary system were 90.40, 72.99, and 80.46%, respectively. These results suggested the competition on active sites of SMC happened among the three antibiotics. The affinities of SMC to three antibiotics followed the order TC > SDZ > CIP. The removal of antibiotics by SMC were mainly attributed to the mechanisms including electrostatic interactions, hydrophobic interactions, hydrogen bonding and so on. This study will provide a technical support for antibiotic wastewater treatment.

Synthesis and Use of Silica Xerogels Doped with Iron as a Photocatalyst to Pharmaceuticals Degradation in Water

The main objective of this study was to assess the photoactive properties of iron-doped silica xerogels under solar radiation. For this purpose, silica xerogels (XGS) synthesized by the sol-gel method were doped with Fe (III) by two routes: impregnation and polymerization. XGS samples were texturally and chemically characterized by N2 adsorption, XRD, FTIR, Raman, SEM-EDX, DRS, and PL, evidencing the suitability of using XGS substrates to host iron clusters on their surface with total compatibility. Chlorphenamine (CPM), ciprofloxacin (CIP), and ranitidine (RNT) were used as model compounds. The degradation of the molecules was made under simulated solar radiation testing the synthesis pad, load, material size, and reuse. It was found that XGS doped with Fe by the impregnation route (XGS-Fe-Im) were able to completely degrade CPM and RNT in 30 min and 10 min, respectively, whilst for CIP it achieved the removal of 60% after 1 h of solar radiation exposure, outperforming parent materials and solar radiation by itself. The study of the degradation mechanism elucidated a major influence from the action of HO• radicals. The present investigation offers a potential route of application of XGS Fe-doped materials for the removal of emerging concern contaminants under near real-world conditions.

Ozone-enhanced TiO2 nanotube arrays for the removal of COVID-19 aided antibiotic ciprofloxacin from water: Process implications and toxicological evaluation

The purpose of this study was to evaluate the performance of synthesized TiO₂ nanotube arrays (NTAs) for the removal of the COVID-19 aided antibiotic ciprofloxacin (CIP) and the textile dye methylene blue (MB) from model wastewater. Synthesis of TiO₂ NTAs showed that anodization potential and calcination temperatures directly influence nanotube formation. The increased anodization potential from 10 to 40 V resulted in the development of larger porous nanotubes with a diameter of 36-170 nm, while the collapse of the tubular structure was registered at the highest applied potential. Furthermore, it was found that the 500 °C calcination temperature was the most prominent for the formation of the most photocatalytically active TiO₂ NTAs, due to the optimal anatase/rutile ratio of 4.60. The degradation of both model compounds was achieved with all synthesized TiO₂ NTAs; however, the most photocatalytically active NTA sample was produced at 30 V and 500 ^°C. Compared to photocatalysis, CIP degradation was greatly enhanced by 5-25 times when ozone was introduced to the photocatalytic cell (rates 0.4-4.2 × 10^-1 min^-1 versus 0.07-0.2 × 10^-1 min^-1). This resulted in the formation of CIP degradation by-products, with different mass-to-charge ratios from [M+H]⁺ 346 to 273 m/z. Even though the CIP degradation pathway is rather complex, three main mechanisms, decarboxylation, hydroxylation reaction, and piperazine ring cleavage, were proposed and explained. Furthermore, treated samples were placed in contact with the crustaceans Daphnia magna. It was found that 100% mortality was achieved when approximately 60% of the remaining TOC was present in the samples, indicating that toxic degradation by-products were formed.

Impact of Antibiotics as Waste, Physical, Chemical, and Enzymatical Degradation: Use of Laccases

The first traces of Tetracycline (TE) were detected in human skeletons from Sudan and Egypt, finding that it may be related to the diet of the time, the use of some dyes, and the use of soils loaded with microorganisms, such as Streptomyces spp., among other microorganisms capable of producing antibiotics. However, most people only recognise authors dating between 1904 and 1940, such as Ehrlich, Domagk, and Fleming. Antibiotics are the therapeutic option for countless infections treatment; unfortunately, they are the second most common group of drugs in wastewaters worldwide due to failures in industrial waste treatments (pharmaceutics, hospitals, senior residences) and their irrational use in humans and animals. The main antibiotics problem lies in delivered and non-prescribed human use, use in livestock as growth promoters, and crop cultivation as biocides (regulated activities that have not complied in some places). This practice has led to the toxicity of the environment as antibiotics generate eutrophication, water pollution, nutrient imbalance, and press antibiotic resistance. In addition, the removal of antibiotics is not a required process in global wastewater treatment standards. This review aims to raise awareness of the negative impact of antibiotics as residues and physical, chemical, and biological treatments for their degradation. We discuss the high cost of physical and chemical treatments, the risk of using chemicals that worsen the situation, and the fact that each antibiotic class can be transformed differently with each of these treatments and generate new compounds that could be more toxic than the original ones; also, we discuss the use of enzymes for antibiotic degradation, with emphasis on laccases.

Photocatalytic degradation of persistent organic pollutants by Co-Cl bond reinforced CoAl-LDH/Bi12O17Cl2 photocatalyst: mechanism and application prospect evaluation

The widespread distribution of persistent organic pollutants (POPs) in natural waters has aroused global concern due to their potential threat to the aquatic environment. Photocatalysis represents a promising mean to remediate polluted waters with the simple assistance of solar energy. Herein, we fabricated a Co-Cl bond reinforced CoAl-LDH/Bi₁₂O₁₇Cl₂ heterogeneous photocatalyst to investigate the feasibility of photocatalysis to treat POPs-polluted water under environmental conditions. The optimum CoAl-LDH/Bi₁₂O₁₇Cl₂ (5-LB) composite photocatalyst exhibited excellent photocatalytic performance, which could degrade 92.47 % of ciprofloxacin (CIP) and 95 % of bisphenol A (BPA) with 2h of actual solar light irradiation in Changsha, China (N 28.12 °, E 112.59 °). In view of the synergistic influence of water constituents, various water matrices greatly affected the degradation rate of CIP (BPA), with the degradation efficiency of 82.17% (84.37%) in tap water, 69.67% (71.63%) in wastewater effluent, and 44.07% (67.7%) in wastewater inflow. The results of electron spin resonance, and chemical trapping experiment, HPLC-MS and density functional theory calculation reflected that the degradation of CIP was mainly attributed to h⁺ and ¹O₂ attacking the active atoms of CIP molecule with high Fukui index. Furthermore, the non-toxicity of both 5-LB photocatalyst and treated CIP solution was proved by E.coli and B.subtilis cultivation, which further demonstrated the feasibility of the 5-LB to treat POPs in real water under irradiation of solar light.

Removal of Chloroacetanilide Herbicides from Water Using Heterogeneous Photocatalysis with TiO2/UV-A

Chloroacetanilide herbicides are widely used in the agricultural sector throughout the world. Because of their poor biodegradability, high water solubility, and long persistence, chloroacetanilide herbicides have a high potential to contaminate water, and conventional water treatment processes do not ensure sufficient removal. Therefore, heterogeneous photocatalysis using TiO2/UV-A was investigated for the degradation of alachlor, acetochlor, and metolachlor from water. Two commercially available TiO2 (P25 and AV-01) were used as photocatalysts. Different experimental setups were also tested. In addition, the toxicity of single herbicides and mixtures of their photocatalytic degradation products to the freshwater alga Chlorella kessleri was investigated via a growth inhibition test. The maximum removal efficiency for alachlor, acetochlor, and metolachlor was 97.5%, 93.1%, and 98.2%, respectively. No significant differences in the removal efficiency of chloroacetanilide herbicides were observed for the photocatalysts used. Although the concentrations of all herbicides during photocatalysis decreased, the toxicity of the resulting mixtures of degradation products increased or remained the same, indicating the formation of toxic degradation products.

Controllable synthesis of a sponge-like Z-scheme N,S-CQDs/Bi2MoO6@TiO2 film with enhanced photocatalytic and antimicrobial activity under visible/NIR light irradiation

Multifunctional photocatalytic surfaces for pollutant degradation and antimicrobial application are often in high demand, however they confront many challenges in charge transfer and light capture ability. In this work, a sponge-like N,S-CQDs/Bi₂MoO₆@TiO₂ film was constructed via hydrothermal technique aiming to solve above problems. As a result, the ternary film showed enhanced photocatalytic efficiency under visible and near-infrared (NIR) light, in which 85.8% and 44.6% of ciprofloxacin (CIP) were degraded after 240 min irradiation with visible and NIR light, respectively. Moreover, the composite film effectively realized photocatalytic sterilization of gram-positive B. subtilis and gram-negative E. coli under visible light irradiation. The bacterial colony decreased significantly from 7.56-log to 1-log cfu/mL after adding the ternary film within 1.5 h. The enhanced photocatalytic efficiency was closely related to both introduction of surface-functional N,S-CQDs and the construction of N,S-CQDs/Bi₂MoO₆@TiO₂ Z-scheme system, in which the transfer efficiency of photoinduced carriers and the light absorption property were significantly improved. We consider that the N,S-CQDs/Bi₂MoO₆@TiO₂ film is promising for the degradation of refractory pollutants and antimicrobial application under visible/NIR light irradiation. The relatively convenient recycling property and excellent photocatalytic performance of the N,S-CQDs/Bi₂MoO₆@TiO₂ film are beneficial for industrial applications.

One-pot synthesis of oxygen-vacancy-rich Cu-doped UiO-66 for collaborative adsorption and photocatalytic degradation of ciprofloxacin

UiO-66, as one of the most stable metal-organic frameworks (MOFs), has attracted a lot of attention in the field of adsorption and photocatalysis. However, this application of UiO-66 is still limited due to either the low accessibility of micropores or the poor electron-hole charge separation capability. This study aims to promote UiO-66 accessibility of micropores and charge separation through the construction of oxygen vacancies (OVs) and mesopore defects as well as copper incorporation. Herein, mesopore Cu doped UiO-66 with rich OVs was synthesized by a one-pot method and demonstrated high efficiency for the removal of ciprofloxacin (CIP) from the aquatic system. First of all, denatured mesopore defects were produced in Cu doped UiO-66 which possessed a 58% increase in specific surface area compared to UiO-66, facilitating the adsorption of molecular oxygen. Secondly, e^- was preferentially trapped by OVs under light irradiation. Electron (e^-) reacted rapidly with the surface adsorbed oxygen to generate superoxide radical (O₂^-). Meanwhile, copper incorporation increased the photocurrent and reduced the interfacial charge transfer resistance, thereby improving the charge separation efficiency. As a result, the adsorption efficiency and photocatalytic performance of mesopore Cu doped UiO-66 with OVs were 8.1 and 3.7 times higher than those of UiO-66, respectively. This study paved a way for the one-step synthesis of MOFs containing OVs and broadened the possibilities of practical applications for photo-induced removal of antibiotics from effluent.

Multifunctional hybrid membranes for photocatalytic and adsorptive removal of water contaminants of emerging concern

This work focuses on the combination of multifunctional photocatalytic and adsorbent materials in a unique polymeric membrane. For this purpose, Au/TiO₂ and Y₂(CO₃)₃ nanoparticles were immobilised onto a poly (vinylidene fluoride-hexafluoropropylene), (PVDF-HFP) membrane, and the physical-chemical characterisation of these materials was performed, as well as pollutant removal efficiency. An efficient TiO₂ functionalisation with gold nanoparticles was achieved, endowing these particles with the capability to absorb visible radiation absorption. A favourable porous structure was obtained for the membranes, with an average pore size of 4 μm, and the nanoparticles immobilisation did not alter the chemical properties of the polymeric membrane. The produced hybrid materials, including both the Au/TiO₂ and Y₂(CO₃)₃ nanoparticles, presented an efficiency of 57% in the degradation of norfloxacin (5 mg/L) under ultraviolet radiation for 120 min, 80% under visible radiation for 300 min, and 58% in arsenic adsorption for 240 min. These membranes represent a new multifunctional platform for removing several pollutants, which may allow their incorporation in more efficient and less energy-consuming water treatment processes favouring its application, even in low energy resources countries.

Antibiotic Resistance in the Drinking Water: Old and New Strategies to Remove Antibiotics, Resistant Bacteria, and Resistance Genes

Bacterial resistance is a naturally occurring process. However, bacterial antibiotic resistance has emerged as a major public health problem in recent years. The accumulation of antibiotics in the environment, including in wastewaters and drinking water, has contributed to the development of antibiotic resistant bacteria and the dissemination of antibiotic resistance genes (ARGs). Such can be justified by the growing consumption of antibiotics and their inadequate elimination. The conventional water treatments are ineffective in promoting the complete elimination of antibiotics and bacteria, mainly in removing ARGs. Therefore, ARGs can be horizontally transferred to other microorganisms within the aquatic environment, thus promoting the dissemination of antibiotic resistance. In this review, we discuss the efficiency of conventional water treatment processes in removing agents that can spread/stimulate the development of antibiotic resistance and the promising strategies for water remediation, mainly those based on nanotechnology and microalgae. Despite the potential of some of these approaches, the elimination of ARGs remains a challenge that requires further research. Moreover, the development of new processes must avoid the release of new contaminants for the environment, such as the chemicals resulting from nanomaterials synthesis, and consider the utilization of green and eco-friendly alternatives such as biogenic nanomaterials and microalgae-based technologies.

Characteristics and mechanisms of ciprofloxacin degradation by black soldier fly larvae combined with associated intestinal microorganisms

Antibiotics are challenging to degrade and are excreted by livestock which results in environmental pollution. In this paper, we demonstrated that environmentally friendly manure bioremediation performed by black soldier fly larvae (BSFL) is a wise alternative, which could effectively degrade ciprofloxacin (CIP) by approached 85.48% in artificial diet and 84.22% in poultry manure within 12 days. They are up to 2.5-4.0 fold more than that achieved by natural fermentation. The five CIP-degrading strains were isolated from the larval gut, two of which, named by Klebsiella pneumoniae BSFLG-CIP1 and Proteus mirabilis BSFLG-CIP5, could degraded CIP by nearly 98.22% and 97.83% in vitro, respectively. When the intestinal isolates were re-inoculated to sterile BSFL system, the degradation level significantly increased up to 82.38%, comparing with the sterile BSFL system (21.76%). It is proved that the larvae intestinal microbiota might carry out this highly-efficient CIP-degradation. Furthermore, seven possible metabolites were identified for CIP-degradation in vitro, and they were referring three main potential degrading mechanisms of hydroxylize, piperazine ring substitute and cleavage, and quinoline ring cleavage. In conclusion, the present study may provide a strategy to reduce antibiotics pollution in animal waste through bioremediation with BSFL and adjusted intestinal microbes.

Process enhancing strategies for the reduction of Cr(VI) to Cr(III) via photocatalytic pathway

This discourse aimed at providing insight into the strategies that can be adopted to boost the process of photoreduction of Cr(VI) to Cr(III). Cr(VI) is amongst the highly detestable pollutants; thus, its removal or reduction to an innocuous and more tolerable Cr(III) has been the focus. The high promise of photocatalysis hinged on the sustainability, low cost, simplicity, and zero sludge generation. Consequently, the present dissertation provided a comprehensive review of the process enhancement procedures that have been reported for the photoreduction of Cr(VI) to Cr(III). Premised on the findings from experimental studies on Cr(VI) reductions, the factors that enhanced the process were identified, dilated, and interrogated. While the salient reaction conditions for the process optimization include the degree of ionization of reacting medium, available photogenerated electrons, reactor ambience, type of semiconductors, surface area of semiconductor, hole scavengers, quantum efficiency, and competing reactions, the relevant process variables are photocatalyst dosage, initial Cr(VI) concentration, interfering ion, and organic load. In addition, the practicability of photoreduction of Cr(VI) to Cr(III) was explored according to the potential for photocatalyst recovery, reactivation, and reuse reaction conditions and the process variables.

Treatment technologies to mitigate the harmful effects of recalcitrant fluoroquinolone antibiotics on the environ- ment and human health

Antibiotic proliferation in the environment and their persistent nature is an issue of global concern as they induce antibiotic resistance threatening both human health and the ecosystem. Antibiotics have therefore been categorized as emerging pollutants. Fluoroquinolone (FQs) antibiotics are an emerging class of contaminants that are used extensively in human and veterinary medicine. The recalcitrant nature of fluoroquinolones has led to their presence in wastewater, effluents and water bodies. Even at a low concentration, FQs can stimulate antibacterial resistance. The main sources of FQ contamination include waste from pharmaceutical manufacturing industries, hospitals and households that ultimately reaches the wastewater treatment plants (WWTPs). The conventional WWTPs are unable to completely remove FQs due to their chemical stability. Therefore, the development and implementation of more efficient, economical, convenient treatment and removal technologies are needed to adequately address the issue. This review provides an overview of the technologies available for the removal of fluoroquinolone antibiotics from wastewater including adsorptive removal, advanced oxidation processes, removal using non-carbon based nanomaterials, microbial degradation and enzymatic degradation. Each treatment technology is discussed on its merits and limitations and a comparative view is presented on the choice of an advanced treatment process for future studies and implementation. A discussion on the commercialization potential and eco-friendliness of each technology is also included in the review. The importance of metabolite identification and their residual toxicity determination has been emphasized. The last section of the review provides an overview of the policy interventions and regulatory frameworks that aid in retrofitting antibiotics as a central key focus contaminant and thereby defining the discharge limits for antibiotics and establishing safe manufacturing practices.

Adsorption and detoxification of pharmaceutical compounds from wastewater using nanomaterials: A review on mechanism, kinetics, valorization and circular economy

Antibiotics overuse, inappropriate conduct, and discharge have led to adverse effects on various ecosystems. The occurrence of antibiotics in surface and drinking water is a matter of global concern. It is responsible for multiple disorders, including disruption of endocrine hormones and high chronic toxicity. The hospitals, pharmaceutical industries, households, cattle farms, and aquaculture are the primary discharging sources of antibiotics into the environment. This review provides complete detail on applying different nanomaterials or nanoparticles for the efficient removal of antibiotics from the diverse ecosystem with a broader perspective. Efforts have been made to focus on the degradation pathways and mechanism of antibiotic degradation using nanomaterials. More light has been shed on applying nanostructures in photocatalysis, which would be an economical and efficient solution. The nanoscale material or nanoparticles have incredible potential for mineralizing pharmaceutical compounds in aqueous solutions at low cost, easy handling characteristics, and high efficacy. Furthermore, nanoparticles can absorb the pharmaceutical by-products and wastes at a minimum cost as they can be easily recycled. With the increasing number of research in this direction, the valorization of pharmaceutical wastes and by-products will continue to expand as we progress from old conventional approaches towards nanotechnology. The utilization of nanomaterials in pharmaceutical wastewater remediation is discussed with a major focus on valorization, energy generation, and minimization and its role in the circular economy creating sustainable development.

Recent advances in structural modifications of photo-catalysts for organic pollutants degradation - A comprehensive review

Over the last few years, industrial and anthropogenic activities have increased the presence of organic pollutants such as dyes, herbicides, pesticides, analgesics, and antibiotics in the water that adversely affect human health and the environment worldwide. Photocatalytic treatment is considered a promising, economical, effective, and sustainable process that utilizes light energy to degrade the pollutants in water. However, certain drawbacks like rapid recombination and low migration capability of photogenerated electrons and holes have restricted the use of photo-catalysts in industries. Hence, despite the abundance of lab-scale research, the technology is still not much commercialized in the mainstream. Several structural modifications in the photo-catalysts have been adopted to enhance the pollutant degradation performance to overcome the same. In this context, the present review article outlines the different advanced heterostructures synthesized to date for improved degradation of three major organic pollutants: antibiotics, dyes, and pesticides. Moreover, the article also emphasizes the degradation kinetics of photo-catalysts and the publication trend in the past decade along with the roadblocks preventing the transfer of technology from the laboratory to industry and new age photo-catalysts for the profitable implications in industrial sectors.

Removal of Pharmaceuticals from Water by Adsorption and Advanced Oxidation Processes: State of the Art and Trends

Pharmaceutical products have become a necessary part of life. Several studies have demonstrated that indirect exposure of humans to pharmaceuticals through the water could cause negative effects. Raw sewage and wastewater effluents are the major sources of pharmaceuticals found in surface waters and drinking water. Therefore, it is important to consider and characterize the efficiency of pharmaceutical removal during wastewater and drinking-water treatment processes. Various treatment options have been investigated for the removal/reduction of drugs (e.g., antibiotics, NSAIDs, analgesics) using conventional or biological treatments, such as activated sludge processes or bio-filtration, respectively. The efficiency of these processes ranges from 20–90%. Comparatively, advanced wastewater treatment processes, such as reverse osmosis, ozonation and advanced oxidation technologies, can achieve higher removal rates for drugs. Pharmaceuticals and their metabolites undergo natural attenuation by adsorption and solar oxidation. Therefore, pharmaceuticals in water sources even at trace concentrations would have undergone removal through biological processes and, if applicable, combined adsorption and photocatalytic degradation wastewater treatment processes. This review provides an overview of the conventional and advanced technologies for the removal of pharmaceutical compounds from water sources. It also sheds light on the key points behind adsorption and photocatalysis.

A simple tactic synthesis of hollow porous graphitic carbon nitride with significantly enhanced photocatalytic performance

Hollow porous graphitic carbon nitride (porous CN) was synthesized via a simple tactic method, and the resulting porous CN showed an effectively modified surface area, crystal structure and enhanced photocatalytic performance. Optical and electrochemical characterization results demonstrated an increase in the charge transfer rate and a decrease in recombination tendency.

Comparison of the Efficiency of Ultraviolet/Zinc Oxide (UV/ZnO) and Ozone/Zinc Oxide (O3/ZnO) Techniques as Advanced Oxidation Processes in the Removal of Trimethoprim from Aqueous Solutions

Nowadays, advanced oxidation processes, particularly photocatalyst process and catalytic ozonation by ZnO nanoparticles, are the most efficient method of eliminating pharmaceuticals. The purpose of this study was to compare the efficiency of ultraviolet/zinc oxide (UV/ZnO) and ozone/zinc oxide (O3/ZnO) techniques as advanced oxidation processes in the removal of trimethoprim (TMP) from aqueous solutions. The process consisted of 0.6 g/L of ozone (O3), pH = 7.5 ± 0.5, TMP with a concentration of 0.5–5 mg/L, ZnO with a dose of 50–500 mg/L, 5–30 min reaction time, and 30–180 min contact time with UV radiation (6 W, 256 nm) in a continuous reactor. The high removal efficiency was achieved after 25 minutes when ZnO is used in 1 mg/L TMP under an operational condition at pH 7.5. When the concentration of the pollutant increased from 0.5 to 1, the average removal efficiency increased from 78% to 94%, and then, it remained almost constant. An increase in the reaction time from 5 to 25 minutes will cause the average elimination to increase from 84% to 94%. The results showed that the efficiency of O3/ZnO process in the removal of TMP was 94%, while the removal efficiency of UV/ZnO process was 91%. The findings exhibited that the kinetic study followed the second-order kinetics, both processes. With regard to the results, the photocatalyst process and catalytic ozonation by ZnO nanoparticles can make acceptable levels for an efficient posttreatment. Finally, this combined system is proven to be a technically effective method for treating antibiotic contaminants.

Application of TiO2-Based Photocatalysts to Antibiotics Degradation: Cases of Sulfamethoxazole, Trimethoprim and Ciprofloxacin

The extensive application of antibiotics in human and veterinary medicine has led to their widespread occurrence in a natural aquatic environment. Global health crisis is associated with the fast development of antimicrobial resistance, as more and more infectious diseases cannot be treated more than once. Sulfamethoxazole, trimethoprim and ciprofloxacin are the most commonly detected antibiotics in water systems worldwide. The persistent and toxic nature of these antibiotics makes their elimination by conventional treatment methods at wastewater treatment plants almost impossible. The application of advanced oxidation processes and heterogeneous photocatalysis over TiO2-based materials is a promising solution. This highly efficient technology has the potential to be sustainable, cost-efficient and energy-efficient. A comprehensive review on the application of various TiO2-based photocatalysts for the degradation of sulfamethoxazole, trimethoprim and ciprofloxacin is focused on highlighting their photocatalytic performance under various reaction conditions (different amounts of pollutant and photocatalyst, pH, light source, reaction media, presence of inorganic ions, natural organic matter, oxidants). Mineralization efficiency and ecotoxicity of final products have been also considered. Further research needs have been presented based on the literature findings. Among them, design and development of highly efficient under sunlight, stable, recyclable and cost-effective TiO2-based materials; usage of real wastewaters for photocatalytic tests; and compulsory assessment of products ecotoxicity are the most important research tasks in order to meet requirements for industrial application.

Therapeutic Applications of Functional Nanomaterials for Prostatitis

Prostatitis is a common disease in adult males, with characteristics of a poor treatment response and easy recurrence, which seriously affects the patient's quality of life. The prostate is located deep in the pelvic cavity, and thus a traditional infusion or other treatment methods are unable to easily act directly on the prostate, leading to poor therapeutic effects. Therefore, the development of new diagnostic and treatment strategies has become a research hotspot in the field of prostatitis treatment. In recent years, nanomaterials have been widely used in the diagnosis and treatment of various infectious diseases. Nanotechnology is a promising tool for 1) the accurate diagnosis of diseases; 2) improving the targeting of drug delivery systems; 3) intelligent, controlled drug release; and 4) multimode collaborative treatment, which is expected to be applied in the diagnosis and treatment of prostatitis. Nanotechnology is attracting attention in the diagnosis, prevention and treatment of prostatitis. However, as a new research area, systematic reviews on the application of nanomaterials in the diagnosis and treatment of prostatitis are still lacking. In this mini-review, we will highlight the treatment approaches for and challenges associated with prostatitis and describe the advantages of functional nanoparticles in improving treatment effectiveness and overcoming side effects.

Therapeutic Applications of Functional Nanomaterials for Prostatitis

Prostatitis is a common disease in adult males, with characteristics of a poor treatment response and easy recurrence, which seriously affects the patient’s quality of life. The prostate is located deep in the pelvic cavity, and thus a traditional infusion or other treatment methods are unable to easily act directly on the prostate, leading to poor therapeutic effects. Therefore, the development of new diagnostic and treatment strategies has become a research hotspot in the field of prostatitis treatment. In recent years, nanomaterials have been widely used in the diagnosis and treatment of various infectious diseases. Nanotechnology is a promising tool for 1) the accurate diagnosis of diseases; 2) improving the targeting of drug delivery systems; 3) intelligent, controlled drug release; and 4) multimode collaborative treatment, which is expected to be applied in the diagnosis and treatment of prostatitis. Nanotechnology is attracting attention in the diagnosis, prevention and treatment of prostatitis. However, as a new research area, systematic reviews on the application of nanomaterials in the diagnosis and treatment of prostatitis are still lacking. In this mini-review, we will highlight the treatment approaches for and challenges associated with prostatitis and describe the advantages of functional nanoparticles in improving treatment effectiveness and overcoming side effects.

Facile synthesis of highly crystalline g-C3N4 nanosheets with remarkable visible light photocatalytic activity for antibiotics removal

g-C₃N₄ has attracted much attention in photocatalysis field because of its good visible light response. However, its photocatalytic activity is still greatly limited by fast carriers recombination and small specific surface. In order to promote carriers separation and pollutants adsorption, a facile synthesis scheme combining hydrothermal method with secondary calcination process under N₂ gas protection was developed, and highly crystalline g-C₃N₄ nanosheets (HCCNNS) were successfully prepared. During ciprofloxacin (CIP) and sulfamethazine (SMZ) degradation, it showed excellent visible light photocatalytic activity, wherein CIP and SMZ with 10 mg/L could achieve degradation efficiency of 98.4% and 96.9% in 60 min under visible light irradiation. Compared with conventional g-C₃N₄, the degradation rate constants were enhanced by 6.9 and 5.8 times, respectively. From the perspectives of morphology, optical property and surface chemistry, the ultra-high activity of HCCNNS is mainly attributed to its highly crystalline structure and nanosheet morphology, which not only reduce the carriers transfer resistance, promote the pollutants adsorption capability, but also expand the light absorption range, and promote the carriers separation. Furthermore, the synthesis procedure of HCCNNS possesses the nature of high yield and excellent cost performance, thus, HCCNNS possesses great potential for mass production and practical application for antibiotics removal.

Novel BiOBr by compositing low-cost biochar for efficient ciprofloxacin removal: the synergy of adsorption and photocatalysis on the degradation kinetics and mechanism insight

C/BiOBr composite materials were synthesized via a simple one-step solvothermal method, with C derived from biochar, which was prepared from the low-cost straw. The samples were characterized by SEM, XRD, XPS and PL. The 2% C/BiOBr composite material showed a noticeable adsorption and photocatalysis synergistic effect to remove CIP. The adsorption rate and degradation rate were 1.45 times and 1.8 times that of BiOBr. The adsorption kinetics and isotherms of CIP on C/BiOBr were analyzed with the pseudo-second-order kinetic and Langmuir models. The degradation efficiency was 96.8% after 60 min of irradiation. High stability and degradability were still maintained after four cycles. The Bi-O-C bond accelerated electron transition and inhibited the rapid photogenerated electron pair recombination. In the degradation process of CIP, ˙O2 - and h+ played a significant role. Experiments proved that C/BiOBr is practical and feasible for the degradation of CIP under the synergistic effect of adsorption and photocatalysis.