Effects of thiol functionalization of a waste-derived activated carbon on the adsorption of sulfamethoxazole from water: Kinetic, equilibrium and thermodynamic studies

Pharmaceuticals removal from aqueous solution by water hyacinth (Eichhornia crassipes): a comprehensive investigation of kinetics, equilibrium, and thermodynamics

This study shows the efficiency of WH-C450, an adsorbent obtained from water hyacinth (WH) biomass, in the removal of sulfamethoxazole (SMX) from aqueous solutions. The process involves calcination of WH at 450 °C to produce an optimal adsorbent material capable of removing up to 73% of SMX and maximum SMX adsorption capacity of 132.23 mg/g. Fourier-transform infrared (FTIR) characterization reveals the involvement of various functional groups in the adsorption process through hydrogen bonds and electron-donor-acceptor (EDA) interactions. X-ray diffraction (XRD) analysis confirms the presence of phases containing CO32-, PO43- ions, as well as elements such as Si and Fe, which contribute to the adsorption mechanism through hydrogen bonding and complexation, respectively. X-ray photoelectron spectroscopy (XPS) analysis further supports these interactions. Kinetic analysis shows rapid adsorption, which combines physical and chemical processes and leads to rapid attainment of equilibrium. This is due to the high affinity of WH-C450 for SMX, which allows for a fast and efficient adsorption process. Isothermal modeling reveals multilayer adsorption with favorable interactions. Thermodynamic analysis confirms the endothermic and temperature-dependent nature of the process. In addition, pH, adsorbent dose, and initial concentration are important in adsorption. Lower pH levels enhance cationic SMX adsorption, while higher adsorbent doses improve efficiency. Optimal conditions were identified by experimental design, enabling the establishment of a predictive model. Consequently, the SMX removal capacity is strongly correlated with the initial concentration. This research underscores the potential of WH-C450 for antibiotic removal in water treatment applications.

Biomimetic cytotoxicity control of select nitrogenous disinfection byproducts in water

Nitrogenous disinfection byproducts (N-DBPs) in water are carcinogenic, teratogenic, and mutagenic. In this work, we developed a biomimetic reduction approach based on the cysteine thiol that destructed the highly toxic, select nitrogenous haloacetamides (HAMs) and haloacetonitriles (HANs) while effectively controlling the cytotoxicity of the degradation products to serve as a basis for further technological applications (e.g. immobilized contact bed for terminal users). Mechanisms on toxicity control were elucidated. Results showed the degradation and cytotoxicity control of HAMs as more efficient than that of the HANs. The cytotoxicity of the chlorinated, brominated, and iodinated HAMs and HANs was reduced to 25 %- 0.25 % of the original after biomimetic reduction using a reasonable concentration ratio. Through a combination of thiol-specific reactivity, dehalogenation, and quantitative structure-activity relationship analyses, the major toxicity control mechanisms were found to be the reductive dehalogenation of the N-DBPs. The halogenated functional groups on the N-DBPs had a more pronounced effect than the amide and nitrile groups on the cytotoxicity and detoxification effect. Patterns of toxicity interaction variations with DBPs concentrations were identified to detect possible synergistic cytotoxicity interactions under various combinations of HAMs and HANs in the presence of the cysteine thiol. Results could benefit future N-DBPs control efforts.

Evaluation of different functionalization methodologies for improving the removal of three target antibiotics from wastewater by a brewery waste activated carbon

This work aims to increase the efficiency of an activated carbon produced from brewery waste (AC) in the removal of three target antibiotics (sulfamethoxazole (SMX), trimethoprim (TMP), and ciprofloxacin (CIP)) by surface incorporation of oxygen, nitrogen or sulfur groups. AC was produced using spent brewery grains (the most abundant waste from the brewing industry) as raw material, K2CO3 as activating agent and microwave energy for pyrolysis. Then, seven different functionalized AC were prepared, characterized for their physicochemical properties, and tested for adsorption (%) of SMX, TMP and CIP from three different matrices (ultrapure water (pH ~5-6), buffered ultrapure water (pH 8), and effluent from a municipal wastewater treatment plant (WWTP effluent (pH 8)), under batch operation. Based on the obtained results, an oxygen functionalized AC was selected for further characterization and studies on the adsorption of the target antibiotics from the WWTP effluent. Kinetic results fitted the pseudo-second order model and the equilibrium isotherms were adequately described by the Langmuir model, reaching maximum adsorption capacities (qm) of 124 ± 1 μmol g-1, 315 ± 2 μmol g-1 and 201 ± 5 μmol g-1 for SMX, TMP and CIP, respectively. The selected functionalization increased qm by up to 58 % in comparison with the non-functionalized AC. The oxygen modified AC produced from a biomass waste remarkably improved its performance for an efficient application in the removal of antibiotics from wastewater.

Nanoplastics increase the toxicity of a pharmaceutical, at environmentally relevant concentrations - A mixture design with Daphnia magna

In aquatic environments, nanoplastics (NPls) can adsorb pharmaceuticals. However, throughout the scientific community, there is scarce knowledge about the interactive effects of the mixture nanoplastics (NPls) with pharmaceuticals to aquatic organisms. Therefore, this study aimed to investigate if the pharmaceutical diphenhydramine (DPH) toxicological effects alters when in presence of polystyrene NPls (PSNPls). To achieve this, Daphnia magna immobilization and different biochemical biomarkers (48-hours exposure) were assessed. Synergistic interactions occurred at environmentally relevant concentrations, PSNPls+DPH induced oxidative damage, whereas no effect was observed at single exposures. With the increase of PSNPls concentration, the DPH concentration causing 50% of effect (EC50) for organisms' immobilization decreased to 0.001 mg/L. In silico analysis suggested that the DPH toxicity to D. magna occurs via the sodium-dependent serotonin transporter. The results showed interactive effects between PSNPls and DPH (implying harmful effects on D. magna), allowing more thoughtful decisions by society and policymakers regarding plastics and pharmaceuticals.

Green synthesis of Ag2O nanoparticles using Punica granatum leaf extract for sulfamethoxazole antibiotic adsorption: characterization, experimental study, modeling, and DFT calculation

Silver oxide (Ag2O) nanoparticles (NPs) were generated by synthesizing green leaf extract of Punica granatum, and afterwards they were used as adsorbent to remove the antibiotic additive sulfamethoxazole (SMX) from aqueous solutions. Prior of their use as adsorbent, the Ag2O NPs were characterized by various methods such as X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy/energy-dispersive X-ray (SEM-EDX), and transmission electron microscopy (TEM). The Ag2O NPs were found to be spherically shaped and stabilized by the constituents of the extract. Further, at SMX antibiotic concentration of 100 mg L-1, the Ag2O NPs achieved almost complete removal of 98.93% within 90 min, and by using 0.8 g L-1 of adsorbent dose at pH=4 and temperature T=308 K. In addition, the experimental data were well fitted with the theoretical Langmuir model indicating homogeneous adsorbed layer of the SMX antibiotic on the Ag2O NPs surface. The maximum uptake capacity was 277.85 mg g-1. A good agreement was also found between the kinetic adsorption data and the theoretical pseudo-second-order model. Regarding the thermodynamic adsorption aspects, the data revealed an endothermic nature and confirmed the feasibility and the spontaneity of the adsorption reaction. Furthermore, the regeneration study has shown that the Ag2O NPs could be efficiently reused for up to five cycles. The geometric structures have been optimized and quantum chemical parameters were calculated for the SMX unprotonated (SMX+/-) and protonated (SMX+) using density functional theory (DFT) calculation. The DFT results indicated that the unprotonated SMX+/- reacts more favorably on the Ag2O surface, as compared to the protonated SMX+. The SMX binding mechanism was predominantly controlled by the electrostatic attraction, hydrogen bond, hydrophobic, and π-π interactions. The overall data suggest that the Ag2O NPs have promising potential for antibiotic removal from wastewater.

Ex-situ magnetic activated carbon for the adsorption of three pharmaceuticals with distinct physicochemical properties from real wastewater

Pharmaceuticals are able to evade conventional wastewater treatments and therefore, are recurrently found in the environment with proven potential to cause harm to human and wildlife. Adsorption onto activated carbon (AC) is a promising complement. However, AC production from non-renewable resources and its difficult after-use recuperation are prohibitive. Hence, a waste-based magnetic activated carbon (MAC) was produced from paper mill sludge, via an ex-situ synthesis, for the adsorptive removal of carbamazepine (CBZ), sulfamethoxazole (SMX) and ibuprofen (IBU) from ultrapure water and wastewater. The MAC was obtained through the promotion of electrostatic interactions between magnetic and activated carbon particles in a water suspension at controlled pH between the points of zero charge of both surfaces. The optimized condition (MACX3) presented remarkable properties regarding specific surface area (S_BET=795 m² g^-1) and saturation magnetization (M_S=19 emu g^-1). Kinetic and equilibrium adsorption studies were performed under batch conditions. Adsorption equilibrium was reached in up to 30 min for all pharmaceuticals in both matrices, proving the low dependence on the adsorbate and the broad applicability of MACX3 in pharmaceutical adsorption. Regarding equilibrium experiments, high Langmuir maximum adsorption capacities (q_m) were achieved in ultrapure water (up to 711 ± 40 µmol g^-1). Equilibrium studies in wastewater revealed a decay in q_m when compared to ultrapure water: 28% for CBZ (468 ± 20 µmol g^-1 (111 ± 5 mg g^-1)), 78% for SMX (145 ± 10 µmol g^-1 (37 ± 3 mg g^-1)) and 62% for IBU (273 ± 8 µmol g^-1 (56 ± 2 mg g^-1)), attributed to the wastewater pH, which dictates the speciation of the pharmaceuticals and controls electrostatic interactions between pharmaceuticals and MAC, and to competition effects by organic matter. It was demonstrated the promising applicability of a waste-based ex-situ MAC, rapidly retrievable from water, as an alternative tertiary wastewater treatment for pharmaceuticals removal.

Recent advances in waste-derived functional materials for wastewater remediation

Water pollution is a major concern for public health and a sustainable future. It is urgent to purify wastewater with effective methods to ensure a clean water supply. Most wastewater remediation techniques rely heavily on functional materials, and cost-effective materials are thus highly favorable. Of great environmental and economic significance, developing waste-derived materials for wastewater remediation has undergone explosive growth recently. Herein, the applications of waste (e.g., biowastes, electronic wastes, and industrial wastes)-derived materials for wastewater purification are comprehensively reviewed. Sophisticated strategies for turning wastes into functional materials are firstly summarized, including pyrolysis and combustion, hydrothermal synthesis, sol-gel method, co-precipitation, and ball milling. Moreover, critical experimental parameters within different design strategies are discussed. Afterward, recent applications of waste-derived functional materials in adsorption, photocatalytic degradation, electrochemical treatment, and advanced oxidation processes (AOPs) are analyzed. We mainly focus on the development of efficient functional materials via regulating the internal and external characteristics of waste-derived materials, and the material's property-performance correlation is also emphasized. Finally, the key future perspectives in the field of waste-derived materials-driven water remediation are highlighted.

Surface imprinted polymer on a metal-organic framework for rapid and highly selective adsorption of sulfamethoxazole in environmental samples

The demand for the removal of pollutants in aqueous solution has triggered extensive studies to optimize the performance of adsorbents, but the adsorption rate and selectivity of adsorbents have been overlooked. Hierarchically ordered porous vinyl-functionalized UIO-66 was used as supporter to prepare a surface molecular imprinted polymer (MIP-IL@UIO-66). The UIO-66 with large specific surface area significantly increased the number of active site of polymer, and so the MIP-IL@UIO-66 can achieve the rapid and highly selective adsorption of sulfamethoxazole (SMZ) in water. The structure and morphology of MIP-IL@UIO-66 was examined using scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption-desorption isotherms, thermogravimetry, X-ray photoelectron spectroscopy, and X-ray powder diffraction. Results indicate that the presented MIP-IL@UIO-66 has an ultrafast equilibrium rate (equilibrium time, 10 min), large adsorption capability (maximum capacity, 284.66 mg g^-1), excellent adsorption selectivity (selectivity coefficient, 11.36), and good reusability (number of cycles, 5 times) via equilibrium adsorption experiments. Subsequently, as a novel solid phase extraction (SPE) adsorbent, the adsorption performance of SMZ onto MIP-IL@UIO-66 was better than that of a commercial SPE adsorbent. A MISPE column combined with high-performance liquid chromatography (HPLC) was presented to detect SMZ in water, soil, egg, and pork samples with recoveries of 91-106%. Hydrogen bonds, electrostatic and π-π interactions, and molecular memory were attributed to recognizing the SMZ of MIP-IL@UIO-66.

Porous carbon aerogel derived from bacterial cellulose with prominent potential for efficient removal of antibiotics from the aquatic matrix

The development of adsorption methods for the remediation of antibiotics pollution in water is hindered by the lack of high-performance sorbents. In this study, a nanofiber carbon aerogel was prepared using bacterial cellulose and its adsorption performances for three common antibiotics (norfloxacin, sulfamethoxazole, and chloramphenicol) in water were evaluated. The as-prepared nanofiber carbon aerogel showed a higher adsorption capacity toward target antibiotics compared to other adsorbents reported in the literature. The maximum adsorption capacities for norfloxacin, sulfamethoxazole, and chloramphenicol were 1,926, 1,264, and 525 mg/g, respectively at 298 K. Notably, the nanofiber carbon aerogel was able to adsorb 80% of the equilibrium adsorption capacity within 1 min and reach equilibrium within 15 min. After five regeneration cycles, the adsorption capacity still reached 1,166, 847, and 428 mg/g for norfloxacin, sulfamethoxazole, and chloramphenicol, respectively. The characterization results showed that the carbon aerogel exhibited a high specific surface area (1,505 m²/g) and a layered porous network structure. Furthermore, the mechanistic study reveals that the enhanced antibiotic adsorption by the as-prepared nanofiber carbon aerogel was attributed to the pore filling effect, hydrogen bonding, hydrophobic effect, electrostatic interaction, and π-π interactions. Overall, these results imply that low-cost and green nanofiber carbon aerogels may be promising adsorbents for the remediation of antibiotic-contaminated wastewater. The materials prepared from natural and readily available bacterial cellulose can adsorb antibiotics efficiently, which provides a reference for the development of adsorbent materials using natural substances.