The potential application of bio-based ceramic/organic xerogel derived from the plant sources: A new green adsorbent for removal of antibiotics from pharmaceutical wastewater

Plant biomass-based nanoparticles for remediation of contaminants from water ecosystems: Recent trends, challenges, and future perspectives

Green nanomaterials can mitigate ecological concerns by minimizing the impact of toxic contaminants on human and environmental health. Biosynthesis seems to be drawing unequivocal attention as the traditional methods of producing nanoparticles through chemical and physical routes are not sustainable. In order to utilize plant biomass, the current review outlines a sustainable method for producing non-toxic plant biomass-based nanoparticles and discusses their applications as well as recent trends involved in the remediation of contaminants, like organic/inorganic pollutants, pharmaceuticals, and radioactive pollutants from aquatic ecosystems. Plant biomass-based nanoparticles have been synthesized using various vegetal components, such as leaves, roots, flowers, stems, seeds, tuber, and bark, for applications in water purification. Phyto-mediated green nanoparticles are effectively utilized to treat contaminated water and reduce harmful substances. Effectiveness of adsorption has also been studied using variable parameters, e.g., pH, initial contaminant concentration, contact time, adsorbent dose, and temperature. Removal of environmental contaminants through reduction, photocatalytic degradation, and surface adsorption mechanisms, such as physical adsorption, precipitation, complexation, and ion exchange, primarily due to varying pH solutions and complex functional groups. In the case of organic pollutants, most of the contaminants have been treated by catalytic reduction and photodegradation involving the formation of NaBH4, H2O2, or both. Whereas electrostatic interaction, metal complexation, H-bonding, π- π associations, and chelation along with reduction have played a major role in the adsorption of heavy metals, pharmaceuticals, radioactive, and other inorganic pollutants. This review also highlights several challenges, like particle size, toxicity, stability, functional groups, cost of nanoparticle production, nanomaterial dynamics, and biological interactions, along with renewability and recycling of nanoparticles. Lastly, this review concluded that plant-biomass-based nanoparticles provide a sustainable, eco-friendly remediation method, utilizing the unique properties of nanomaterials and minimizing chemical synthesis risks.

Performance of magnetic nanocomposite based on xanthan gum-grafted-poly(acrylamide) crosslinked by borax for the effective elimination of amoxicillin from aquatic environments

This study evaluated the effectiveness of using nanocomposite (NCs) of xanthan gum grafted polyacrylamide crosslinked Borax - iron oxide nanoparticle (XG-g-pAAm-CL-Borax-IONP) to remove the amoxicillin antibiotic (AMX) from an aquatic environment. To confirm the structural characteristics of the prepared XG-g-pAAm-CL-Borax-IONP NCs, unique characterization methods (XRD, FT-IR, FE-SEM, EDX, BET, TGA, Zeta, and VSM) were used. Adsorption experimental setups were performed with the influence of solution pH (4-9), the effect of adsorbent dose (0.003-0.02 g), the effect of contact time (5-45 min), and the effect of initial AMX concentration (50-400 mg/L) to achieve the most efficient adsorption conditions. Based on the Freundlich isotherm model, XG-g-pAAm-CL-Borax-IONP NCs provided the maximum AMX adsorption capacity of 1183.639 mg/g. This research on adsorption kinetics also established that the pseudo-second-order model (R2 = 0.991) is outstanding compatibility with the experimental results. AMX adsorption on the NCs may occur through intermolecular hydrogen bonding, diffusion, and trapping into the polymer network. Even after five cycles, these NCs still displayed the best performance. Based on these results, XG-g-pAAm-CL-Borax-IONP NCs may be a viable material for the purification of AMX from contaminated water.

From wastewater to clean water: Recent advances on the removal of metronidazole, ciprofloxacin, and sulfamethoxazole antibiotics from water through adsorption and advanced oxidation processes (AOPs)

Antibiotics released into water sources pose significant risks to both human health and the environment. This comprehensive review meticulously examines the ecotoxicological impacts of three prevalent antibiotics-ciprofloxacin, metronidazole, and sulfamethoxazole-on the ecosystems. Within this framework, our primary focus revolves around the key remediation technologies: adsorption and advanced oxidation processes (AOPs). In this context, an array of adsorbents is explored, spanning diverse classes such as biomass-derived biosorbents, graphene-based adsorbents, MXene-based adsorbents, silica gels, carbon nanotubes, carbon-based adsorbents, metal-organic frameworks (MOFs), carbon nanofibers, biochar, metal oxides, and nanocomposites. On the flip side, the review meticulously examines the main AOPs widely employed in water treatment. This includes a thorough analysis of ozonation (O3), the photo-Fenton process, UV/hydrogen peroxide (UV/H2O2), TiO2 photocatalysis, ozone/UV (O3/UV), radiation-induced AOPs, and sonolysis. Furthermore, the review provides in-depth insights into equilibrium isotherm and kinetic models as well as prospects and challenges inherent in these cutting-edge processes. By doing so, this review aims to empower readers with a profound understanding, enabling them to determine research gaps and pioneer innovative treatment methodologies for water contaminated with antibiotics.

Research on Green Adsorbents

Adsorption processes play a crucial role in air purification, wastewater treatment, soil remediation technologies, noble metals recovery, and long-term energy storage systems [...].

The engineering of defect-modified boron nitride ribbons: an effective adsorbent to rapid capture for tetracycline

Antibiotics, the persistent organic pollutants, have brought serious pollution to the aquatic environment. Therefore, it is necessary to select rapid adsorbents to remove them from their long-term threat. Herein, the introduction of defects in BN was employed to enhance its surface chemical activity for rapid capture of tetracycline via hydrothermal and calcination methods. The defect content in BN can be controlled by adjusting the volume ratio of ethanol to water. Among them, when the volume ratio of H2O/ethanol is 4/1 (BN-3), BN-3 has the most N defects at 33%, which increases the adsorption rate of h-BN for TC and promotes the adsorption capacity to 302.15 mg g-1, which is due to the introduction of nitrogen defects significantly regulates the electronic structure of BN. The corresponding theoretical calculations confirm that BN with N defects decreases the absorption energy of BN for TC. Additionally, the adsorption removal rate of tetracycline still reached 95.5% after 5 cycles of TC adsorption by BN-3, indicating that the defect-modified BN has good reusability and is beneficial for its use in pollutant adsorption.

Ferrocene crosslinked and functionalized chitosan microspheres towards bio-based Fenton-like system for the removal of organic pollutants

Dye-containing wastewater treatment has been a major long-term global challenge. For this purpose, a novel bio-based microspheres (CS-FC) with high specific surface area (63.24 m2·g-1) and nano-channels (17.95 nm) was prepared using chitosan as the framework and ferrocene as a crosslinking active group. CS-FC not only has the ability to rapidly enrich methyl orange (MO) through hydrogen-bonding and electrostatic attraction, but also almost completely degrades it in the presence of H2O2/K2S2O8 through a synergistic radical/non-radical mechanism under the activating effect of ferrocene. Without H2O2/K2S2O8, the maximum MO adsorption capacity of CS-FC is in the range 871-1050 mg·g-1, and conforms to a Langmuir isothermal model with pseudo-second-order kinetics. In the presence of H2O2/K2S2O8, the removal of MO dramatically increased from 32 % to nearly 100 % after incubation for 60 min, due to the simultaneous formation of highly reactive 1O2 and ·OH. The significant contribution from 1O2 endowed CS-FC/H2O2/K2S2O8 with high universality for degrading various organic pollutants (including azo dyes and antibiotics), a wide pH window (2-8), and low sensitivity to co-existing ions. Such cost-effective, recyclable porous bio-based microspheres are suitable for heterogeneous Fenton-like catalysis in organic wastewater treatment that rely on synergistic radical/non-radical reaction pathways.

Green and low-temperature synthesis of the magnetic modified biochar under the air atmosphere for the adsorptive removal of heavy metal ions from wastewater: CCD-RSM experimental design with isotherm, kinetic, and thermodynamic studies

The accumulation of heavy metal ions in living cells leads to biological damage, which makes the necessity of using new methods to effectively remove heavy metal ions from the environment more vital. In this work, a magnetic modified biochar was prepared under regular air atmosphere and low temperature (220 ºC) and used as a low-cost and green adsorbent for efficient adsorptive removal of cobalt (Co(II)) and Lead (Pb(II)) ions from contaminated waters. The adsorption process was modeled and optimized using CCD-RSM to maximize the removal efficiency of heavy metal ions, as well as was monitored in detail by isotherm, kinetic, and thermodynamic studies. The results show that the Langmuir maximum adsorption capacity of the adsorbent reached 237.92 mg g-1 (single) and 121.23 mg g-1 (binary) for Co(II) and 207.21 mg g-1 (single) and 106.56 mg g-1 (binary) for Pb(II) under the short time of 25 min and solution pH of 6.0. The kinetic studies revealed that the pseudo-first-order model was the best-fitted model to experimental data and indicated that the adsorption process was mostly through chemisorption. Also, thermodynamic studies showed that that adsorptive removal of Co(II)and Pb(II)ions followed an endothermic and spontaneous process. The reusability studies demonstrated that the adsorbent could be successfully regenerated with 5 mL of 0.1 mol L-1 HNO3 solution, and the adsorption efficiency was retaining about 90% after four adsorption-desorption cycles. Also, the results from using real water samples, including drinking water, groundwater, and river water, implied that the synthesized magnetic modified biochar was highly efficient for practical treatment processes. Overall, the results indicated that the proposed magnetic biochar can be considered as a cost-effective and efficient adsorbent for adsorptive removal of heavy metal ions from contaminated waters.

Novel Ag-bridged dual Z-scheme g-C3N4/BiOI/AgI plasmonic heterojunction: Exceptional photocatalytic activity towards tetracycline and the mechanism insight

Rational design and synthesis of highly efficient and robust photocatalysts with positive exciton splitting and interfacial charge transfer for environmental applications is critical. Herein, aiming at overcoming the common shortcomings of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers and unstable structure, a novel Ag-bridged dual Z-scheme g-C₃N₄/BiOI/AgI plasmonic heterojunction was successfully synthesized using a facile method. Results showed that Ag-AgI nanoparticles and three-dimensional (3D) BiOI microspheres were decorated highly uniformly on the 3D porous g-C₃N₄ nanosheet, resulting in a higher specific surface area and abundant active sites. The optimized 3D porous dual Z-scheme g-C₃N₄/BiOI/Ag-AgI manifested exceptional photocatalytic degradation efficiency of tetracycline (TC) in water with approximately 91.8% degradation efficiency within 165 min, outperforming majority of the reported g-C₃N₄-based photocatalysts. Moreover, g-C₃N₄/BiOI/Ag-AgI exhibited good stability in terms of activity and structure. In-depth radical scavenging and electron paramagnetic resonance (EPR) analyses confirmed the relative contributions of various scavengers. Mechanism analysis indicated that the improved photocatalytic performance and stability were ascribed to the highly ordered 3D porous framework, fast electron transfer of dual Z-scheme heterojunction, desirable photocatalytic performance of BiOI/AgI and synergistic effect of Ag plasmas. Therefore, the 3D porous Z-scheme g-C₃N₄/BiOI/Ag-AgI heterojunction had a good prospect for applications in water remediation. The current work provides new insight and useful guidance for designing novel structural photocatalysts for environment-related applications.

Activated carbon modified titanium dioxide/bismuth trioxide adsorbent: One-pot synthesis, high removal efficiency of organic pollutants, and good recyclability

Considerable endeavors have focused on tightly combining adsorption with photocatalysis in designing composite materials for environmental pollution treatment. Recent advances in coupling titanium dioxide/bismuth trioxide (TiO₂/Bi₂O₃) with activated carbon (AC) show significantly enhanced photocatalytic performance but face critical limitations including low adsorption capacity and multi-step synthesis. In this work, we introduce a one-pot synthesis of activated carbon modified TiO₂/Bi₂O₃ composite materials (TiO₂/Bi₂O₃/AC). Thanks to the integrated adsorbent/photocatalyst system, TiO₂/Bi₂O₃/AC shows a drastically enhanced removal efficiency for sulfamethazine (>81%), far beyond the corresponding value of the reported AC/TiO₂/Bi₂O₃ adsorbent (<40%). Notably, the removal rates of other typical pollutants including tetracyclines, methyl orange, and rhodamine B are as high as >98%. Furthermore, TiO₂/Bi₂O₃/AC obtains >80% of its adsorption rate for the fifth cycle after simple photo-regeneration without any other post-treatments. Kinetic analysis and photoelectric characterization are carried out to provide insight into adsorption mechanism. Therefore, this work demonstrates a considerable potential to design and construct other multifunctional adsorbents with advanced performance.

Mechanosynthesis of magnolol multicomponent crystalline solids for improved natural antibiotics and customizable release profiles

Antibiotic is one of the most important discoveries in human and animal medicine. However, the inefficient use of antibiotics has caused widespread and persistent contamination of ecosystems, setting off microbial resistance storms. Magnolol is a botanical antibiotic, but poor physicochemical properties result in low bioavailability. Increasing solubility of magnolol can help to reduce the doses of medications to patients, minimize bothersome side effects. In this work, three novel multicomponent crystalline solids were synthesized from magnolol and isomeric coformers by mechanochemistry. It was found that the multicomponent crystalline solids achieved the customizable release profile of magnolol by manipulating the substituent positions of the isomers and complexation. Antibacterial activity test showed that bioactivity on two bacteria was considerably improved by designed MGN multicomponent crystals. In addition, the coformers controlled the dissolution behavior and further stabilized the improvement according to the variable statistical analysis. In conclusion, the properties of antibiotic multicomponent solids can be manipulated through the coformers. This provides an effective strategy for managing the release of drugs to meet individual biological differences and diverse therapeutic needs.

Strong and robust cellulose-based enzymatic membrane with gradient porous structure in dynamically catalytic removal of sulfonamides antibiotics

Enzyme membrane systems (EMS) have generated considerable interest because of their advantages of accelerating reactions, eliminating product inhibition, and enhancing conversion rates. However, there are deficiencies in the efficient fabrication of affinity carrier membranes and dynamic catalytic separation properties. Herein, a strong and highly flexible spunlaced viscose/bacterial cellulose (BC) composite membrane in situ embedded with graphene oxide (GO) was developed by combining a scalable bio-synthesis method with atom transfer radical polymerization technology. Notably, the layer-by-layer growth of BC on composite film and the addition of GO resulted in an entangled network with strong hydrogen bonding, endowing the resulting membrane with superior mechanical properties and flexibility, while facilitating a gradient structure and porous transport channels. Subsequently, a novel and highly efficient EMS was constructed by using abundant molecular brushes on composite membrane as immobilized enzyme carrier. The resulting EMS exhibited a high throughput (2.17 L/min*m²) and an interception rate (98.64%) in dynamic catalytic sulfonamide antibiotic wastewater activated with syringaldehyde mediator. Meanwhile, the removal rates of sulphapyridine and sulfamethazine were 97.20% and 94.78% under 0.14 MPa and 15 min, respectively. This efficient and scalable manufacturing strategy is of great significance and may pave a novel pathway for antibiotics wastewater treatment and recycling.

One-Step Synthesis of a Mn-Doped Fe2O3/GO Core-Shell Nanocomposite and Its Application for the Adsorption of Levofloxacin in Aqueous Solution

This study describes for the first time the synthesis, characterization, and application of a MnFe₂O₃/GO core-shell nanocomposite as an adsorbent for the removal of levofloxacin (Lev) from real water samples. The formation of the proposed nanocomposite was confirmed using various characterization techniques. The structural techniques revealed a 20 nm average particle size of the MnFe₂O₃/GO core-shell nanocomposite, with a surface area of 70.7 m² g^-1, as shown by the BET results. The most influential parameters (adsorbent dosage, stirring rate, and Lev pH) that affected the adsorption process were optimized using the response surface methodology (RSM) based on a central composite design. The optimum conditions were 0.007 g, 2, and 7 for adsorbent dosage, stirring rate, and Lev pH, respectively. The adsorption behavior of Lev on the MnFe₂O₃/GO core-shell nanocomposite was examined using isotherm models, kinetics, and thermodynamics. The kinetic models demonstrated that the adsorption process was controlled by both intraparticle and outer diffusion. Furthermore, the results obtained revealed that the adsorption of Lev on MnFe₂O₃/GO was dominated by electrostatic interactions. Moreover, Dubinin-Radushkevich and Temkin isotherms confirmed that the sorption mechanism was dominated by electrostatic interactions, while Langmuir and Sips models confirmed a monolayer adsorption process. The maximum adsorption capacity of Lev onto the MnFe₂O₃/GO adsorbent was found to be 129.9 mg g^-1. Furthermore, the thermodynamic data revealed that the adsorption system was spontaneous and exothermic. The synthesized MnFe₂O₃/GO core-shell nanocomposite showed significant recyclability and regenerability properties up to five adsorption-desorption cycles. As a proof of concept, the performance of the prepared adsorbent was evaluated for laboratory-scale purification of spiked real water samples. The prepared adsorbent significantly reduced the concentration of Lev in the real water samples and the removal efficiency ranged from 86 to 97%.

A silanized magnetic amino-functionalized carbon nanotube-based multi-ion imprinted polymer for the selective aqueous decontamination of heavy metal ions

A novel adsorbent comprising a silanized magnetic amino-functionalized carbon nanotube-based multi-ion imprinted polymer is introduced as an ideal candidate for the simultaneous and selective adsorptive remediation of heavy metal ions from contaminated water.