Optimization of ciprofloxacin degradation in wastewater by homogeneous sono-Fenton process at high frequency

Sono-Triggered Biomimetically Nanoantibiotics Mediate Precise Sequential Therapy of MRSA-Induced Lung Infection

Bacterial-induced lower respiratory tract infections are a growing global health concern, exacerbated by the inefficacy of conventional antibiotics and delivery methods to effectively target the lower respiratory tract, leading to suboptimal therapeutic outcomes. To address this challenge, this work engineers PBP2a antibody-presenting membrane nanovesicles (AMVs) specifically designed to target the penicillin-binding protein variant on the surface of methicillin-resistant Staphylococcus aureus (MRSA). Concurrently, this work develops pure ciprofloxacin nanoparticles (NanoCip) that, for the first time, exhibits exceptional self-generated sonodynamic properties, attributed to hydrogen-bond-driven self-assembly, while maintaining their inherent pharmacological efficacy. These NanoCip particles are integrated with AMVs to create a novel biomimetic nanomedicine, AMV@NanoCip. This formulation demonstrated remarkable MRSA-targeting affinity in both in vitro and in vivo models, significantly enhancing antibacterial activity. Upon ultrasound stimulation, AMV@NanoCip achieves over 99.99% sterilization of MRSA in vitro, with a reduction exceeding 5.14 Log CFU. Prokaryotic transcriptomic analysis further elucidates the synergistic mechanisms by which AMV@NanoCip, coupled with ultrasound, disrupts the MRSA exoskeleton. In a MRSA-induced pneumonia animal model, AMV@NanoCip+US results in a substantial bacterial load reduction in the lungs (99.99%, 4.02 Log CFU). This sequential treatment strategy (adhesion-membrane disruption-synergistic therapy) offers significant promise as an innovative therapeutic approach for combating bacterial infections.

Occurrence, distribution, and ecological risks of antibiotics and antibiotic resistance genes in the surface waters of Gaoyou Lake, China

This work examined the occurrence characteristics and ecological risks of 31 antibiotics across five classes and seven ARGs in the surface waters of Gaoyou Lake. A total of 27 antibiotics, spanning four classes, were detected in the surface waters of Gaoyou Lake, with an overall concentration ranging from 57.5 to 114 ng/L and an average of 78.8 ng/L. Sulfonamide antibiotics exhibited the highest average concentration at 32.7 ng/L. Spatial analysis revealed that antibiotic concentration levels in the western region of the lake were higher than those in other areas. Similarly, ARGs were most abundant in this area, with sulfonamide ARGs demonstrating a notably higher mean abundance than other ARGs. Correlation analysis revealed strong positive associations between sul1 and several antibiotics, including sulfadimidine, sulfamethoxazole, ciprofloxacin, lincomycin, clindamycin, erythromycin, and intl1 (P < 0.05), with intra-group correlations among sulfonamide ARGs exceeding those between different ARG groups. Ecological risk assessment indicated that erythromycin and sulfamethoxazole presented medium risks, whereas roxithromycin, azithromycin, and lincomycin were associated with low risks to aquatic organisms. The ecological risk proportions across monitoring sites were primarily low (10.6%) and moderate (16.7%), with no high-risk areas identified and 72.7% presenting no risk. The cumulative ecological risk quotient (RQcum) suggested a medium-risk level at all surveyed sites.

Synergistic degradation of Tris (2-Chloroethyl) Phosphate (TCEP) by US/Fenton system: Experimental, DFT calculation and toxicity evaluation

Organophosphorus esters (OPEs), exemplified by tris (2-chloroethyl) phosphate (TCEP), find extensive application in diverse industries such as construction materials, textiles, chemical manufacturing, and electronics, consequently resulting in an increased concentration of these compounds in industrial wastewater. The fundamental objective of this investigation was to examine the degradation of TCEP through the implementation of US/Fenton oxidation techniques in a solution. The findings revealed that the US/Fenton system effectively facilitated the degradation of TCEP, with the Chan kinetic model precisely elucidating the degradation process. Under optimized reaction conditions, the degradation efficiency of TCEP reached an impressive 93.18%. However, the presence of common co-existing aqueous substrates such as Cl-, HCO3-, H2PO4-, and HA hindered the degradation process. Bursting tests and electron paramagnetic resonance (EPR) studies affirmed ∙OH oxidation as the principal mechanism underlying TCEP degradation. Detailed degradation pathways for TCEP were established through the utilization of density-functional theory (DFT) calculations and GC/MS tests. Moreover, the ecotoxicological evaluation of TCEP and its intermediates was conducted using the Toxicity Estimation Software Tool (T.E.S.T.).

The Evolution of Sonochemistry: From the Beginnings to Novel Applications

Sonochemistry is the use of ultrasonic waves in an aqueous medium, to generate acoustic cavitation. In this context, sonochemistry emerged as a focal point over the past few decades, starting as a manageable process such as a cleaning technique. Now, it is found in a wide range of applications across various chemical, physical, and biological processes, creating opportunities for analysis between these processes. Sonochemistry is a powerful and eco-friendly technique often called "green chemistry" for less energy use, toxic reagents, and residues generation. It is increasing the number of applications achieved through the ultrasonic irradiation (USI) method. Sonochemistry has been established as a sustainable and cost-effective alternative compared to traditional industrial methods. It promotes scientific and social well-being, offering non-destructive advantages, including rapid processes, improved process efficiency, enhanced product quality, and, in some cases, the retention of key product characteristics. This versatile technology has significantly contributed to the food industry, materials technology, environmental remediation, and biological research. This review is created with enthusiasm and focus on shedding light on the manifold applications of sonochemistry. It delves into this technique's evolution and current applications in cleaning, environmental remediation, microfluidic, biological, and medical fields. The purpose is to show the physicochemical effects and characteristics of acoustic cavitation in different processes across various fields and to demonstrate the extending application reach of sonochemistry. Also to provide insights into the prospects of this versatile technique and demonstrating that sonochemistry is an adapting system able to generate more efficient products or processes.

Removal of methylene blue and azo reactive dyes from aqueous solution and textile effluent via modified pulsed low-frequency ultrasound cavitation process

Organic dyes in the aqueous solutions and textile effluents cause severe environmental pollution due to their carcinogenic and mutagenic nature. Ultrasound (US) cavitation is one of the promising advanced oxidation processes (AOP) to remove the organic dyes from the aqueous solutions and textile effluents. Nevertheless, the conventional low-frequency US cavitation process exhibits very low efficiency in the dye removal process and demands effective modification to improve its performance. In this investigation, a conventional pulsed low-frequency (22 ± 2 kHz) US cavitation process has been modified by varying the US power (50-150 W), initial solution pH (2-10), and O₂ flow rate (1-4 L min^-1) to enhance the decomposition of cationic methylene blue (MB) dye in an aqueous solution. The operation of the classic Haber-Weiss reaction, both in the forward and backward directions, and the ozone effect have been observed, for the first time, under the modified US cavitation process, as confirmed via the radical trapping experiments. Moreover, the hydrothermally synthesized hydrogen titanate (H₂Ti₃O₇) nanotubes (HTN) have been utilized as sonocatalyst, for the first time, for 100% dye removal, with effective regeneration obtained via an in-situ thermal activation of persulfate (PS, S₂O₈^2-). The most optimum values of US power, initial solution pH, O₂ flow rate, HTN, and PS concentrations for 100% MB decomposition are observed to be 150 W, 2, 2 L min^-1, 0.3 g L^-1, and 10 mM, respectively. The decomposition of industrial azo reactive dyes in an aqueous solution as well as in a textile effluent has also been demonstrated using a modified pulsed low-frequency US cavitation process involving the thermal activation of PS without the use of HTN, which justifies its suitability for a commercial application.

Mechanism analysis of hydroxypropyl guar gum degradation in fracture flowback fluid by homogeneous sono-Fenton process

An effective hybrid system was applied as the first report for the successful treatment of key pollutants (hydroxypropyl guar gum, HPG) in fracturing flowback fluid, and the synergistic index of the hybrid system was 20.45. In this regard, chemical oxygen demand (COD) removal ratio was evaluated with various influencing operating factors including reaction time, H2O2 concentration, Fe2+ concentration, ultrasonic power, initial pH, and temperature. The optimal operating parameters by single-factor analysis method were: the pH of 3.0, the H2O2 concentration of 80 mM, the Fe2+ concentration of 5 mM, the ultrasonic power of 180 W, the ultrasonic frequency of 20-25 kHz, the temperature of 39 ℃, the reaction time of 30 min, and the COD removal rate reached 81.15 %, which was permissible to discharge surface water sources based on the environmental standards. A possible mechanism for HPG degradation and the generation of reactive species was proposed. Results of quenching tests showed that various impacts of the decomposition rate by addition of scavengers had followed the order of EDTA-2Na < BQ < t-BuOH, therefore OH radicals had a dominant role in destructing the HPG. Based on the kinetic study, it was concluded that Chan Kinetic Model was more appropriate to describe the degradation of HPG. Identification of intermediates by GC-MS showed that a wide range of recalcitrant compounds was removed and/or degraded into small molecular compounds effectively after treatment. Under the optimal conditions, the sono-Fenton system was used to treat the fracturing flowback fluid with the initial COD value of 675.21 mg/L, and the COD value decreased to 80.83 mg/L after 60 min treatment, which was in line with the marine sewage discharge standard. In conclusion, sono-Fenton system can be introduced as a successful advanced treatment process for the efficient remediation of fracture flowback fluid.

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.

Enhanced Adsorption, Photocatalytic Degradation Efficiency of Phenol Red Using CuZnAl Hydrotalcite Synthesized by Co-Precipitation Technique

ZnAlCO3 hydrotalcite materials modified by Cu2+ ions were synthesized by the co-precipitation method according to the molar ratios of (Cu2+ + Zn2+):Al3+ as 7:3. Thus, the modified materials contain various molar ratios of Cu2+ from 0–3.5 in the samples. The synthesized materials were characterized by X-ray diffraction pattern (XRD), FT–IR, EDS, SEM, the N2 adsorption/desorption isotherm (BET), and UV–Vis DRS spectrum. The synthesized materials were characterized by a layered double hydroxide structure—such as hydrotalcite. The specific surface area BET increases slightly, corresponding to the increasing Cu2+ molar ratios, and the bandgap energy Eg decreases accordingly. Especially, these material samples have a high phenol red (PR) adsorption capacity at a concentration of 100 ppm and PR was degraded under a 30 W LED light with over 90% of conversion efficiency in the presence of 1.2 mL of 30% H2O2 solution. In addition, the CuH–3.5 material sample maintained stability after four times catalytic reuse. Therefore, this material can be used as an effective treatment for the wastewater of the sedge mat weaving village.

Removal of Organics from Landfill Leachate by Heterogeneous Fenton-like Oxidation over Copper-Based Catalyst

Landfill leachates are a mixture of high concentration organic and inorganic contaminants and need to be appropriately treated due to their toxicity and severe adverse effects on the environment. Here, we studied the treatment of landfill leachate through a heterogeneous Fenton-like oxidation process using a zirconia supported copper catalyst (Cu/ZrO2). Reaction conditions such as pH, amount of catalyst, oxidant dose, temperature, and reaction time were investigated and their effects on pollutant abatement discussed. AOS (average oxidation state) and COS (carbon oxidation state) parameters were used for the evaluation of the degree of oxidation of the process, obtaining some insight into the formation of oxidized intermediates (partial oxidation) and the total oxidation (mineralization) of the leachate during the reaction. A two-step oxidation process enhanced the overall performance of the reaction with an abatement of organic compounds of 92% confirming the promising activity of a copper-based catalyst for the treatment of liquid waste. Higher catalytic activity was achieved when the following reaction conditions were applied: 70 °C, pH 5, 200 mg/L of catalyst, 30 mL/L of H2O2 dose, and 150 min. In addition, durability of the catalyst under optimized reaction conditions was verified by repeated reaction cycles.

Fe3O4@N-doped carbon derived from dye wastewater flocculates as a heterogeneous catalyst for degradation of methylene blue

The study used wastewater to mitigate pollution, wherein the catalyst was derived from MG dye wastewater flocculates produced by electrocoagulation.

Synergistic effect of sonication on photocatalytic oxidation of pharmaceutical drug carbamazepine

Photocatalytic, sono-photocatalytic oxidation of pharmaceutical drug of carbamazepine was successfully carried out using Ag/AgCl supported BiVO4 catalyst. For this purpose, firstly, photocatalytic oxidation was optimized by central composite design methodology and then synergistic effect of sonication was investigated. Low frequency (20 kHz) probe type and high frequency (850 kHz) plate type sonication at pulse and continuous mode were studied to degrade the carbamazepine (CBZ) containing wastewater. Pulse duties of 1:5 and 5:1 (on : off) were tested using the high frequency sonication system in the sono-photocatalytic oxidation of CBZ. The effects of frequency, power density measured from calorimetry by changing amplitudes were discussed in the sono-photocatalytic oxidation of CBZ. Complete carbamazepine removal was achieved at the optimum conditions of 5 ppm CBZ initial concentration with 1.5 g/L of catalysts loading and at an alkaline pH of 10 at the end of 4 h of photocatalytic reaction under visible LED light irradiation. Both low frequency and high frequency sonication systems caused an increase in photocatalytic efficiency in a shorter treatment time of 60 min. CBZ removal increased from 44% to 65.42% in low frequency sonication of 20 kHz at the amplitude of 20% (0.15 W/mL power density). In the case of high frequency ultrasonic system (850 kHz), CBZ removal increased significantly from 44% to 89.5 % at 75% amplitude (0.12 W/mL power density) within 60 min of reaction. Continuous mode sonication was observed to be more effective than that of pulse mode sonication not only for degradation efficiency and also for electrical energy consumption needed to degrade CBZ. Sono-catalytic oxidation was also conducted with simulated wastewater that contains SO42-, CO32-, NO3-, Cl- anions and natural organic component of fulvic acid. The CBZ degradation was inhibited slightly in the presence of NO3- and Cl-, and fulvic acid, however, the existence of SO42- and CO32- increased the degradation degree of CBZ. Toxicity tests were performed to determine the toxicity of untreated CBZ, and treated CBZ by photocatalytic, and sono-photocatalytic oxidations.

Optimization and statistical analysis of sono-Fenton treated wastewater of food industry using reactor by response surface method

The present study deals with the treatment of complex waste (WW) treated for removal of chemical oxygen demand (COD) of the food industry by a sono-Fenton process using a batch reactor. The response surface methodology (RSM) was employed to investigate the five independent variables, such as reaction time, the molar ratio of H2O2/Fe2+, volume ratio of H2O2/WW, pH of waste, and ultrasonic density on COD removal. The experimental data was optimized. The optimization yields the conditions: Reaction time of 24 min, HP:Fe molar ratio of 2.8, HP:WW volume ratio of 1.9 ml/L, pH of 3.6 and an ultrasonic density of 1.8 W/L. The predicted value of COD was 91% and the experimental result was 90%. The composite desirability value (D) of the predicted percent of COD removal at the optimized level of variables was close to one (D = 0.991).

Sonochemical processes for the degradation of antibiotics in aqueous solutions: A review

Antibiotic residues in water are general health and environmental risks due to the antibiotic-resistance phenomenon. Sonication has been included among the advanced oxidation processes (AOPs) used to remove recalcitrant contaminants in aquatic environments. Sonochemical processes have shown substantial advantages, including cleanliness, safety, energy savings and either negligible or no secondary pollution. This review provides a wide overview of the different protocols and degradation mechanisms for antibiotics that either use sonication alone or in hybrid processes, such as sonication with catalysts, Fenton and Fenton-like processes, photolysis, ozonation, etc.

Utilization of MWCNTs/Al2O3 as adsorbent for ciprofloxacin removal: equilibrium, kinetics and thermodynamic studies

In the present study, the adsorption behavior of ciprofloxacin (CIP) from aqueous solution onto MWCNTs/Al₂O₃ was studied using batch experiments. Physical characterization of MWCNTs/Al₂O₃ was determined by SEM, XRD, and BET. The effective parameters investigated included: initial CIP concentration, contact time, MWCNTs/Al₂O₃ mass, and temperature. Based on experimental results and correlation coefficients, the rate of CIP adsorption followed the pseudo-second-model kinetics. Complete compatibility of the adsorption isotherm process was achieved with the Langmuir model, and the maximum adsorption capacity reached 41.73 mg/g under the optimized conditions (pH = 7, MWCNTs/Al₂O₃ dose = 1.2 g/L, contact time = 60 min, initial concentration = 10 mg/L, and temperature= 45 °C). The adsorption capacities based on the Langmuir model at different temperatures, 273, 288, 303, and 318 K, were equal to 72.18, 75.92, 79.65, and 83.47 mg/g, respectively. The determined parameters of the thermodynamic studies demonstrated the endothermic and spontaneous nature of the biosorption. The mean free energy was estimated from D-R isotherm model to be 0.316-0.707 KJ/mol, which clearly proved that the adsorption experiment followed a physical process. The data suggest that MWCNTs/Al₂O₃ could be used as a highly effective adsorbent material with a high capacity for the removal of antibiotics from water and wastewater.

Emerging pollutants-Part II: Treatment

Recently, emerging pollutants (EPs) have been frequently detected in urban wastewater, surface water, drinking water, and other water bodies. EPs mainly usually include pharmaceuticals and personal care products, endocrine-disrupting chemicals, antibiotic resistance genes, persistent organic pollutants, disinfection by-products, and other industrial chemicals. The potential threat of EPs to ecosystems and human health has attracted worldwide attention. Therefore, how to treat EPs in various water bodies has become one of the research priorities. In this paper, some research results on treatment of EPs published in 2018 were summarized. PRACTITIONER POINTS: At present, more attention has been paid to emerging pollutants (EPs), including pharmaceuticals and personal care products (PPCPs), endocrine-disrupting chemicals (EDCs), antibiotic resistance genes, persistent organic pollutants, disinfection by-products, etc. Existing EPs disposal technologies mainly include: engineered wetlands and natural systems, biological treatment, physical and physicochemical separation, chemical oxidation, catalysis, etc. This paper reviews some research results on the treatment technologies of EPs published in 2018.