Removal Of Diclofenac Research Articles

Enhanced diclofenac adsorption and degradation using iron‐loaded modified spent bleaching earth carbon in the presence of clofibric acid: mechanistic insights and toxicity assessment

AbstractBACKGROUNDThe presence of pharmaceutical active substances such as diclofenac (DCF) and clofibric acid (CA) in aquatic environments poses significant ecological threats. Existing treatments have not fully explored the impact of CA on DCF removal efficiency. This research introduces nZVI/CTAB‐SBE@C, a novel adsorbent developed from industrial spent bleaching earth (SBE), modified with cetyltrimethylammonium bromide (CTAB) and nano zero‐valent iron (nZVI), enhancing both adsorption and degradation of DCF and CA.RESULTSThis study investigated the impact of CA on the removal capabilities of nZVI/CTAB‐SBE@C for DCF in a coexisting system. Systematic examinations were conducted on the effects of various parameters, including reaction time, dosage, temperature, actual wastewater, humic acid content and coexisting ions. Results indicated that the presence of CA significantly enhanced the DCF removal efficiency, achieving an optimal rate of 87.3% under conditions of reaction time 2 h, adsorbent dosage 5 g L−1 and temperature 25 °C. Moreover, interactions between Al3+ ions and the adsorbent matrix notably improved removal efficiencies for both DCF and CA. Analysis revealed that CA facilitated new degradation pathways for DCF, including hydroxylation and decarboxylation reactions. Additionally, the presence of CA reduced the toxicity of degradation intermediates, enhancing environmental safety compared to systems containing only DCF.CONCLUSIONThis study effectively transforms industrial waste into the efficient nZVI/CTAB‐SBE@C adsorbent. The presence of CA not only boosts DCF removal efficiency but also promotes its safer degradation, thereby reducing the ecological impact of contaminants. © 2024 Society of Chemical Industry (SCI).

Performance of pharmaceutical products removal in a bioelectrochemical system at low temperatures and changes in microbial communities and antibiotic resistance genes.

Biological methods do not effectively remove pharmaceutical products (PPs) and antibiotic resistance genes (ARGs) from wastewater at low temperatures, leading to environmental pollution. Therefore, anaerobic-aerobic-coupled upflow bioelectrochemical reactors (AO-UBERs) were designed to improve the removal of PPs at low temperatures (10 ± 2 °C). The result shows that diclofenac (DIC) and ibuprofen (IBU) removals in the system with aerobic anodic and anaerobic cathodic chambers were 91.7% and 94.7%, higher than that in the control system (12.2 ± 1.5%, 36.5 ± 5.9%), and aerobic zone favors DIC and IBU removal; fluoroquinolone antibiotics (FQs) removals in the system with aerobic cathodic and anaerobic anodic chambers were 17.5-22.4% higher than that in the control system (9.1-22.4%), and anaerobic zone favors FQs removal. Analysis of microbial community structure and ARGs showed that different electrotrophic microbes (Flavobacterium, Acinetobacter, and Delftia) with cold-resistant ability to degrade PPs were enriched in different electrode combinations, and the aerobic cathodic chambers could remove certain ARGs. These results showed that AO-UBERs under intermittent electrical stimulation mode are an alternative method for the effective removal of PPs and ARGs at low temperatures.

A novel two stages chemical activation of pinewood waste for removing organic micropollutants from water and wastewater

The prevalent presence of pharmaceuticals in aquatic ecosystems underscores the necessity for developing cost-effective techniques to remove them from water. The utilization of affordable precursors in producing activated carbon, capable of rivaling commercial alternatives, remains a persistent challenge. The adsorption of diclofenac and ciprofloxacin onto a novel pinewood-derived activated carbon (FPWAC) was explored, employing a sequential activation process involving ammonium nitrate (NH4NO3) treatment followed by sodium hydroxide (NaOH) activation. The produced FPWAC was then thoroughly characterized by employing several techniques. The removal of diclofenac and ciprofloxacin in water and real wastewater effluent was examined in batch tests. The optimum removal conditions were an FPWAC dosage of 1 g L−1, pH 6, mixture concentration of 25 mg L−1, and a temperature of 25 °C. The FPWAC was able to remove both pharmaceuticals for up to six cycles, with more than 95% removal for water and 90% for wastewater in the first cycle. The adsorption performance fitted well with the non-linear Freundlich isotherm for both pollutants. The kinetics of adsorption of diclofenac followed a pseudo-first-order model, while ciprofloxacin showed adherence to the pseudo-second-order model. FPWAC proved its potency as a low-cost adsorbent for pharmaceutical removal from wastewater.

Persulfate photolysis and limited irrigation of recycled wastewater for turfgrass growth: Accumulation of pharmaceutical and personal care products and physiological responses

Recycled wastewater effluent irrigation and implementing limited irrigation rates are two promising strategies for water conservation in agriculture. However, one major challenge is the accumulation and translocation of Pharmaceutical and Personal Care Products (PPCPs) from recycled water to crops. This study investigated the effects of UV persulfate (UV/PS) treatment of recycled water and limited irrigation rate on PPCPs accumulation and physiological responses of St. Augustine turfgrass via a 14-week field trial. Carbamazepine (CBZ), sulfamethoxazole (SMX), triclosan (TCS), fluoxetine (FLX) and diclofenac (DCF) were spiked at 0.1–1.5 µg/L into recycled water and two limited irrigation rates corresponding to 60 % and 80 % of reference Evapotranspiration (ETo) were applied. Results showed that UV/PS removed 60 % of CBZ and > 99 % of other PPCPs from recycled water. Irrigation with UV/PS treated recycled water resulted in approximately a 60 % reduction in CBZ accumulation and complete removal of SMX, DCF, FLX and TCS in both turfgrass leaves and roots. A more limited irrigation rate at 60 % ETo resulted in a higher accumulation of CBZ accumulation compared to 80 % ETo. Similarly, the canopy temperature increased under 60 % ETo irrigation rate compared to 80 % ETo, suggesting that turfgrass under 60 % ETo was more prone to water stress. Applying a 60 % ETo irrigation rate was not sufficient to maintain the turfgrass quality in the acceptable range. A negative correlation between the visual quality and cumulative mass of PPCPs in turfgrass leaves at different irrigation rates was observed, yet irrigation rate was the major driver of turfgrass overall quality and health. Insights from this study will help to integrate recycled water with treatment and limited irrigation, thereby enhancing agricultural water reuse practices.

Enhanced Selective Degradation of Pharmaceutical and Personal Care Products by β-Cyclodextrin-Decorated ZIF-67 Nanocomposites in Reclaimed Water.

A peroxymonosulfate oxidation system was developed via modification of β-cyclodextrin (β-CD) on the surface of Fe2+-doped ZIF-67 (CD/Fe@ZIF-67) as an activator. The 99.7% carbamazepine, 91.3% bisphenol A (BPA), and 95.4% diclofenac (DCF) degradation efficiency were achieved within 10 min, 60, and 1 min, respectively. The hydrophobicity of these three pollutants is positively correlated with their adsorption kinetic constants by CD/Fe@ZIF-67 due to the introduction of β-CD. Scavenger experiments and electron spin resonance spectra confirmed that carbamazepine was preferentially oxidized by SO4•- [λ(SO4•-)(70.5%) > λ(•OH)(28.2%) > λ(O2•-)(1.3%)], where SO4•- and O2•- played dominant roles in the degradation of BPA [λ(SO4•-)(71.7%) > λ(O2•-)(22.8%) > λ(•OH)(5.5%)], and O2•- was responsible for DCF removal [λ(O2•-) = 93.2%]. Additionally, the particulate catalyst was immobilized in the shell side of a ceramic membrane in a membrane reactor for catalyst recovery. This reactor achieved nearly 100% removal efficiency under optimal conditions: 0.036 wt % catalyst loading, 0.5 mM peroxymonosulfate concentration, 1 L inflow, 10 mg/L initial carbamazepine concentration, and 0.012 L/min hydraulic retention time. In summary, this study elucidates the active role of β-CD in a polymetallic/peroxymonosulfate system and provides valuable insights into the development of effective oxidation methods for pharmaceutical and personal care products in wastewater.

Process optimization for the removal of sodium diclofenac from water using a green polymeric membrane

New polymeric membranes for water treatment have been regularly developed and reported by the scientific community; however, process optimization based on the application purpose is necessary to achieve the best performance. In this work, a previously developed “green” polymeric membrane was employed to investigate the influence of process parameters on the removal of sodium diclofenac (DCF) from water. The “green” classification relies on the membrane components (poly(vinyl alcohol) – PVA, citric acid, glycerol, and green synthesized silver nanoparticles) and the mild conditions for its preparation. The parameters studied were the compaction and operational pressure (1.0 – 5.0 bar), feed temperature (10 – 25 °C), DCF concentration (0.002 – 0.010 g L−1), and feed pH (4.0 – 10.0). The results showed a positive influence of pressure on DCF removal (from 54 % to 75 %, within a range of 1.0–5.0 bar) due to the PVA structure densification, as well as the temperature (from 61 % to 82 %, within a range of 10–25 °C) because of the increased water affinity. The DCF concentration influenced the absorption of DCF into the membrane, reaching the maximum of 73 % of DCF removal at 0.007 – 0.010 g L−1. The feed pH determined the mechanism of removal but had a minor influence on the final performance (from 73 % of DCF removal at acidic pH to 77 % at alkaline conditions). The optimized conditions of 5 bar, 25 °C, 0.008 g L−1 DCF, and pH ∼5.75 promoted a permeability of 0.024 L m−2 h−1 bar−1 with 80 % DCF removal. This performance is comparable to that observed for commercial nanofiltration membranes but offers the advantage of a membrane fabricated and operated using a sustainable approach.

Environmental life cycle assessment of UV-C LEDs vs. mercury lamps and oxidant selection for diclofenac degradation

This study is the first environmental comparison between a UV-C LED lamp (emitting at 265 nm) and mercury lamps employed in a lab-scale photoreactor for water treatment purification purposes, using the removal of diclofenac as a case study. Ex-ante life cycle assessment (LCA) methodology was used as a robust method to identify hotspots and recommendations at the early stage of the UV-C LEDs technology. The functional unit was defined as “the treatment of 1 L of polluted water with 20 mg L−1 of diclofenac to achieve a 90% removal of the contaminant”, while the system boundaries include the production and the operation of the photoreactors, following a cradle-to-gate approach. Several scenarios were explored, and overall, the UV-C LED lamp shows a promising environmental performance, with less or similar potential impacts than the mercury lamps in the 16 categories selected from the Environmental Footprint (EF) method. In particular, it reveals less impact in “human toxicity non-cancer” and “resource use minerals and metals” and presents electricity as the main source of impact. Given the higher efficacy of the UV-driven advanced oxidation processes compared to the UV irradiation alone, and since no studies have previously been conducted on the sustainability of free chlorine (FC) as an oxidant in water treatment, a comparison between UV-C, UV-C/H2O2, and UV-C/FC while employing the 265 nm UV-C LED lamp was also assessed. UV-C/H2O2 was more sustainable than UV-C/FC for the same treatment time, but both led to an overall impact reduction of 35% and 30%, respectively. To increase sustainability, employing cleaner energy sources such as photovoltaic or wind energy also resulted in an 80% and 93% reduction in the “climate change” category. Overall, this study demonstrates that using UV-C LEDs and the selected oxidants for water purification is beneficial and encourages the scale-up of the system.

Removal of diclofenac by photocatalysis utilizing crosslinked chitosan/oil-palm embedded titanium dioxide

Abstract Photocatalytic degradation of diclofenac from aqueous solution utilizing cross-linked chitosan/oil palm ash embedded titanium dioxide composite beads (TiO2-COPA) was studied. Fourier Transform Infrared Spectroscopy (FTIR) was established to identify the functional groups of the composite beads. In order to conduct a kinetic and isotherm analysis, a number of parameters were taken into account, initial diclofenac concentration (10–50 mg L−1) and the dosage of composite beads (0.2–0.4 g). When compared to other concentrations, the initial concentration of diclofenac at 10 mg L−1 had the highest degradation percentage (51.32 %). With 69.32 % degradation, 0.4 g of titanium TiO2-COPA composite beads showed the greatest percentage. Photocatalytic degradation kinetics data were evaluated using pseudo-first order and pseudo-second order models. The rate constants for these models for under different initial concentrations were assessed. Kinetic studies proved that the photocatalysis conformed with the pseudo-first-order model. Langmuir Hinshelwood was utilized to analyze the equilibrium data at different diclofenac concentrations.

Removal of Diclofenac from Contaminated Water using Organoclay as Reactive Material

في هذه الدراسة ، تم ازالة المادة الدوائية الديكلوفيناك (Diclofenac) من المياه الملوثة عن طريق الامتزاز على البنتونيت المعدل. تم تغيير البنتونايت من مادة محبة للماء إلى كارهة للماء باستخدام بروميد الأمونيوم ثلاثي ميثيل هيكساديسيل (HTAB). استخدمت التجارب الدفعية لدراسة تأثير عدد من العوامل على كفاءة عملية الامتزاز. هذه العوامل هي: زمن التلامس ، ودرجة الحموضة (pH) للمحلول ، وسرعة الخلط ، وتركيز الملوث الأولي (Co) ، وجرعة المادة الممتزة. تم تحقيق أقصى إزالة للديكلوفيناك (97٪) في الحالات التالية: زمن التلامس 100 دقيقة ، ودرجة الحموضة 7 ، وسرعة الخلط 200 دورة في الدقيقة ، والتركيز الأولي لـ Co 50 جزء في المليون ، والجرعة الممتزة 0.3 جم بينتونيت لكل 100 مل من المحلول الملوث. تم استخدام الفحص المجهري الإلكتروني للماسح الضوئي (SEM) والتحليل الطيفي للأشعة تحت الحمراء لتحويل فورييه (FTIR) لتشخيص صفات المادة الممتزة (البنتونايت المعدل ). وجد ان موديل Langmuir هو الأنسب لتمثيل البيانات التجريبية التي تم الحصول عليها في المختبر. تم دراسة حركية عملية الامتزاز ووجد انها تتمثل بشكل جيد بتفاعل زائف من الدرجة الثانية. كانت عملية الامتزاز ماصة للحرارة وتلقائية ، وفقًا لتحليلات الديناميكا الحرارية.

In-depth study of adsorption mechanisms and interactions in the removal of pharmaceutical contaminants via activated carbon: a physicochemical analysis.

This study presents a theoretical analysis of the adsorption process of pharmaceutical pollutants, specifically acetaminophen (ATP) and diclofenac (DFC), onto activated carbon (AC) derived from avocado biomass waste. The adsorption isotherms of ATP and DFC were analyzed using a multilayer model, which revealed the formation of two to four adsorption layers depending on the temperature of the aqueous solution. The saturation adsorption capacities for ATP and DFC were 52.71 and 116.53mg/g, respectively. A steric analysis suggested that the adsorption mechanisms of ATP and DFC involved a multi-molecular process. The calculated adsorption energies (ΔE1 and ΔE2) varied between 12.86 and 22.58kJ/mol, with the highest values observed for DFC removal. Therefore, the adsorption of these organic molecules was associated with physisorption interactions: van der Waals forces and hydrogen bonds. These findings enhance the understanding of the depollution processes of pharmaceutical compounds using carbon-based adsorbents and highlight the potential of utilizing waste biomass for environmental remediation.

Properties and Possibilities of Using Biochar Composites Made on the Basis of Biomass and Waste Residues Ferryferrohydrosol Sorbent.

Biochar enriched with metals has an increased potential for sorption of organic and inorganic pollutants. The aim of the research was to identify the possibility of using biochar composites produced on the basis of waste plant biomass and waste FFH (ferryferrohydrosol) containing iron atoms, after CO2 capture. The composites were produced in a one-stage or two-stage pyrolysis process. Their selected properties were determined as follows: pH, ash content, C, H, N, O, specific surface area, microstructure and the presence of surface functional groups. The produced biochar and composites had different properties resulting from the production method and the additive used. The results of experiments on the removal of methylene blue (MB) from solutions allowed us to rank the adsorbents used according to the maximum dye removal value achieved as follows: BC1 (94.99%), B (84.61%), BC2 (84.09%), BC3 (83.23%) and BC4 (83.23%). In terms of maximum amoxicillin removal efficiency, the ranking is as follows: BC1 (55.49%), BC3 (23.51%), BC2 (18.13%), B (13.50%) and BC4 (5.98%). The maximum efficiency of diclofenac removal was demonstrated by adsorbents BC1 (98.71), BC3 (87.08%), BC4 (74.20%), B (36.70%) and BC2 (30.40%). The most effective removal of metals Zn, Pb and Cd from the solution was demonstrated by BC1 and BC3 composites. The final concentration of the tested metals after sorption using these composites was less than 1% of the initial concentration. The highest increase in biomass on prepared substrates was recorded for the BC5 composite. It was higher by 90% and 54% (for doses of 30 g and 15 g, respectively) in relation to the biomass growth in the soil without additives. The BC1 composite can be used in pollutant sorption processes. However, BC5 has great potential as a soil additive in crop yield and plant growth.

Assessment of molecularly imprinted polymers for selective removal of diclofenac from wastewater by laboratory and pilot-scale adsorption tests

This study investigated the potential of Molecularly Imprinted Polymers (MIPs) to integrate schemes for wastewater reuse and to serve as effective adsorbent for the removal of a target emerging contaminant (i.e., diclofenac – DCF), after or within pilot scale anaerobic biological treatments. Batch tests were performed to evaluate the effect on DCF removal during anaerobic biological processes by enriching activated sludge of an Upflow Anaerobic Sludge Blanket (UASB) reactor (TSS =19.6 g/L), and an Anaerobic Membrane Bioreactor (AnMBR) (TSS = 120 mg/L) reactors with MIPs (3 mg/L). Therefore, tertiary treatments were investigated by columns adsorption tests that were performed first at lab scale using DCF (15 mg/L) solution in deionized water, and then in-site by treating the anaerobic permeate effluent from the AnMBR at pilot scale level (DCF 500 μg/L). Clogging or blockage of the column bed was not observed during these field tests, where the saturation process of MIPs was slower compared to laboratory tests that used deionized water. In addition, the empirical Thomas Model, Yoon-Nelson Model, Dose-Response Model and Adam Bohart Model showed very good fittings with the experimental data obtained during experiments performed with both synthetic water and anaerobic effluents showing their suitability for the description of breakthrough curves. Finally, it was observed that after regeneration the MIPs can be efficiently reused since adsorption capacity is sufficiently preserved.

Oxygen and phosphorus-enriched mesoporous biowaste-based carbonaceous material: A sustainable solution for efficient removal of diclofenac and chromium (VI) from polluted water

In response to the current environmental crisis, this study focuses on converting biowaste into phosphorus-oxygen-rich activated hydrochar (AH) for removing persistent pollutants such as Diclofenac (DCF) and chromium (VI) (Cr (VI)) from polluted water. The AH was prepared via hydrothermal carbonization of argan nut shells followed by H3PO4 activation under an oxygen-rich atmosphere. The obtained AH was characterized by a high specific surface area of 1879 m2g−1, remarkable mesoporosity, and wide pore diameters. The AH was further analyzed revealing its highly aromatic nature, as well as the abundance of phosphorus and oxygen functional groups on its surface. These properties led to high adsorption capacities of diclofenac and chromium (VI) of 240 mgg−1 and 539 mgg−1, respectively. The investigations indicated that the AH applied physical and chemical forces for removing Cr (VI), while the uptake of DCF molecules was governed by physical forces. Indeed, the high aromaticity and oxygen functionality of AH facilitated the DCF adsorption through hydrogen bonding, π-π interactions, and pore-filling. Meanwhile, the oxygen functionality and the oxygen and phosphorus electron-providing sites on the AH’s surface favor the removal of Cr (VI) ions through physical and chemical interactions, including electrostatic attractions, ion exchange, complexation, and oxidation–reduction reactions. These findings highlight the effectiveness of AH in the elimination of DCF and Cr (VI) from polluted water.

Sunlight removal of diclofenac using g-C3N4, g-C3N4/Cl, g-C3N4/Nb2O5 and g-C3N4/TiO2 photocatalysts

This study aimed to investigate four photocatalysts, whether element-doped (g-C3N4/Cl) or through heterojunctions (g-C3N4/Nb2O5 and g-C3N4/TiO2), and compare against unmodified (bare) g-C3N4 for diclofenac removal under artificial sunlight. The synthesis methodologies were deliberately chosen for simplicity to enable practical applications. Additionally, the potential phytotoxicity of the products was investigated. In this sense, the main novelty of the present work is to contribute to elucidate the performance of photocatalysts commonly employed in photocatalysis (such as Nb2O5 and TiO2), but combined with a material that allows them to be photoactive under visible irradiation. Under the experimental conditions of this study (C0= 20 mgL−1; Ccat. = 600 mgL−1; pH = 6.0; artificial sunlight: 40 Wm−2 UVA, 245 Wm−2 VIS), the four photocatalysts displayed no statistically significant differences in diclofenac removal over the 240-minute evaluation period. However, the specific constant rate normalized by SBET indicated that bare g-C3N4 demonstrated statistically superior efficacy in diclofenac removal. When exposed to natural sunlight, bare g-C3N4 achieved a 68-minute normalized illumination time (t30w) to remove over 67% of diclofenac. Assessing phytotoxicity involved 14 assays using the four photocatalysts and two seed types (cucumber and lettuce). With a few exceptions (g-C3N4, g-C3N4/Cl, and g-C3N4/TiO2, limited to cucumber seeds), experiments revealed non-phytotoxic byproducts after diclofenac photocatalysis, as indicated by germination indices exceeding 80%.

Tuning the wettability of alginate-based nanocomposite beads for efficient removal of pharmaceuticals from water

Long-term exposure to pharmaceuticals, such as diclofenac (DCF) and tetracycline (TC), poses various risks to human health, including antibiotic resistance and endocrine disruption. In this work, we investigated the removal of DCF and TC from water and probed the removal performance of contaminants in a complex matrix consisting of DCF and TC mixtures using alginate (AL)-based nanocomposite beads with tunable wettability. We improved the selectivity of the beads towards hydrophobic contaminants by reducing graphene oxide (GO) to rGO in the presence of AL using a mild and green reducing agent (Vitamin C). Thein-situchemical reduction of GO in AL matrix resulted in amphiphilic rGO-containing beads,as confirmed by several characterization techniques.Thein-situreduction, apart from restoring the sp2hybridized carbon, greatly improved the mechanical properties and stability of the nanocomposite, ensuring reusability beyond 10 adsorption/desorption cycles.Compared to neat AL beads, the addition of only 3.5% rGO (AL:3.5rGO) improved the beads adsorption capacity for TC and DCF by 660% and 747%, respectively. The beads exhibited remarkable performance in the simultaneous removal of TC and DCF from contaminant mixtures. The superior performance of AL:3.5rGO beads is attributed to the enhanced π-π interactions between the aromatic rings of the contaminants and the sp2domains of rGO-containing adsorbents.

Investigating a batch-flow photocatalytic LED system for diclofenac removal in wastewater treatment plants: Assessing the influence of reaction conditions on photocatalytic efficiency

This work introduces an innovative batch-flow photocatalytic LED system aimed at efficiently removing diclofenac from wastewater. The study highlights the novelty of fabricating TiO2-loaded carbon fiber photocatalysts through a hydrothermal process, exhibiting a blue shift in their absorption spectrum and enhancing their photon absorption capability. A crucial design feature is the spectral matching between the LED light source and the photocatalyst, which is critical for achieving high photodegradation efficiency. A significant innovation of our study is the testing of the system under real conditions at an operational sewage treatment plant. Here, the designed system demonstrated high efficacy in degrading diclofenac across various treatment stages, highlighting its robustness and adaptability to changing environmental conditions. The highest degradation efficiency was achieved with sewage from the secondary settling tank, where nearly 90 % efficiency was observed after 6 h of irradiation. Moreover, the use of renewable energy sources emphasizes the system's sustainability, presenting a greener alternative to traditional wastewater treatment methods. The investigation not only showcases the system's effectiveness in diclofenac degradation but also its adaptability and stability under real-world conditions, marking a significant advancement in sustainable wastewater treatment technologies.

Optimized design of quaternary amino-functionalized chitosan fibers for ultra-high diclofenac adsorption from wastewater

The extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from water bodies is imperative due to the potential harm to humans and the ecosystem caused by NSAID-contaminated water. Quaternary amino-functionalized epichlorohydrin cross-linked chitosan fibers (QECFs), an economical and eco-friendly adsorbent, were successfully prepared using a simple and gentle method for efficient diclofenac (DCF) adsorption. Additionally, the optimized factors for the preparation of QECFs included epichlorohydrin concentration, pH, temperature, and (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHTAC) concentration. QECFs demonstrated excellent adsorption performance for DCF across a broad pH range of 7–12. The calculated maximum adsorption capacity and the amount of adsorbed DCF per adsorption site were determined to be 987.5 ± 20.1 mg/g and 1.2 ± 0.2, respectively, according to the D-R and Hill isotherm models, at pH 7 within 180 min. This performance surpassed that of previously reported adsorbents. The regeneration of QECFs could be achieved using a 0.5 mol/L NaOH solution within 90 min, with QECFs retaining their original fiber form and experiencing only a 9.18% reduction in adsorption capacity after 5 cycles. The Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy were used to study the characterization of QECFs, the preparation mechanism of QECFs, and the adsorption mechanism of DCF by QECFs. Quaternary ammonium groups (R4N+) were well developed in QECFs through the reaction between amino/hydroxyl groups on chitosan and CHTAC, and approximately 0.98 CHTAC molecule with 0.98 R4N+ group were immobilized on each chitosan monomer. Additionally, these R4N+ on QECFs played a crucial role in the removal of DCF.

Synthesis of recyclable and light-weight graphene oxide/chitosan/genipin sponges for the adsorption of diclofenac, triclosan, and microplastics

Emerging micropollutants, such as pharmaceuticals and microplastics (MPs), have become a pressing water environmental concern. The aim of this study is to synthesize chitosan sponges using graphene oxide (GO) and genipin (GP) for the removal of pharmaceuticals (diclofenac (DCF) and triclosan (TCS)) and MPs, verify their adsorption mechanisms, evaluate the effects of temperature, pH, and salinity on their adsorption capacities, and determine their reusability. The GO5/CS/GP sponge exhibited a macroporous nature (porosity = 95%, density = 32.6 mg/cm3). GO and cross-linker GP enhanced the adsorption of DCF, TCS, and polystyrene (PS) MPs onto the CS sponges. The adsorption of DCF, TCS, and PS MPs involved multiple steps: surface diffusion and pore diffusion of the sponge. The adsorption isotherms demonstrated that Langmuir model was the most fitted well model to explain adsorption of TCS (qm = 7.08 mg/g) and PS MPs (qm = 7.42 mg/g) on GO5/CS/GP sponge, while Freundlich model suited for DCF adsorption (qm = 48.58 mg/g). DCF adsorption was thermodynamically spontaneous and endothermic; however, the adsorption of TCS and PS MPs was exothermic (283–313 K). The optimal pH was 5.5–7 due to the surface charge of the GO5/CS/GP sponge (pHzpc = 5.76) and ionization of DCF, TCS, and PS MPs. As the salinity increased, DCF removal efficiency drastically decreased due to the weakening of electrostatic interactions; however, TCS removal efficiency remained stable because TCS adsorption was mainly caused by hydrophobic and π–π interactions rather than electrostatic interaction. The removal of PS MPs was enhanced by the electrostatic screening effects of high Na+ ions. PS nanoplastics (average size = 26 nm) were removed by the GO5/CS/GP sponge at a rate of 73.0%, which was better than that of PS MPs (41.5%). In addition, the GO5/CS/GP sponge could be recycled over five adsorption–desorption cycles.

Green synthesis of carbon nanotubes functionalized with iron nanoparticles and coffee husk biomass for efficient removal of losartan and diclofenac: Adsorption kinetics and ANN modeling studies

The presence of emerging contaminants in wastewater poses a global environmental challenge, requiring the development of innovative materials or methods for their treatment. This study focused on the production of green functionalized carbon nanotubes (CNTs) and using them in the adsorption of the pharmaceuticals Losartan (LOS) and Diclofenac (DIC). The efficiency of the methodology was verified by characterization techniques. Elemental composition analysis indicated a significant increase in the iron content after the green functionalization, proving the effectiveness of the method. Thermogravimetric analysis showed similar thermal degradation profiles for pristine CNTs and functionalized CNTs, indicating better post-functionalization thermal stability. BET analysis revealed mesoporous characteristics of CNTs, with increased surface area and pore volumes after functionalization. X-Ray diffraction confirmed the preservation of the lattice structure of the CNTs post-functionalization and post-adsorption, with changes in peak broadening suggesting surface modifications. LOS and DIC adsorption were evaluated via kinetic studies at four different concentrations (0.1–0.4 mmol/L) that were best represented by the pseudo-second order model, suggesting chemisorption mechanisms, with faster and higher uptakes for DIC (0.084–0.261 mmol/g; teq = 5 min) when compared to LOS (0.058–0.235 mmol/g; teq = 20 min). The curves were also studied via artificial neural networks (ANN) and revealed that the best ANN architecture for representing the experimental data is a network with [3 5 5 2] neurons trained using the Bayesian-Regularization algorithm and the Log-sigmoid (hidden layers) and Linear (output layer) transfer functions. The desorption study showed that CaCl2 had better performance in CNT regeneration, reaching its removal capacity above 50% up to 3 cycles, for both pharmaceuticals. These findings reveal the potential of the developed material as a promising adsorbent for targeted removal of pollutants, contributing to advances in the remediation of emerging contaminants and the application of artificial intelligence in adsorption research.

Construction of bismuth based MOF for efficient removal of sodium diclofenac via adsorption and photocatalysis

The mass production and widespread use of Pharmaceuticals and Personal Care Products (PPCPs) have posed a serious threat to the water environment and public health. In this work, a green metal-based Metal Organic Framework (MOF) Bi-NH2-BDC was prepared and characterized, and the adsorption characteristics of Bi-NH2-BDC were investigated with typical PPCPs—diclofenac sodium (DCF). It was found that DCF mainly covered the adsorbent surface as a single molecular layer, the adsorption reaction was a spontaneous, entropy-increasing exothermic process and the adsorption mechanisms between Bi-NH2-BDC and DCF were hydrogen bonding, π-π interactions and electrostatic interactions. In addition, Bi-NH2-BDC also had considerable photocatalytic properties, and its application in adsorbent desorption treatment effectively solved the problem of secondary pollution, achieving a green and sustainable adsorption desorption cycle.