Search Results (413)

In recent years, industrial wastewater discharge containing heavy metals has increased significantly and has adversely affected both human health and the aquatic ecosystem. The increasing demand for metals in industry has prompted researchers to focus on developing effective and economical methods for removal of these metals. In this study, the removal of Ni(II) from wastewater using the Graphene oxide@Fe₃O₄@Pluronic-F68 (GO@Fe₃O₄@Pluronic-F68) nano composite as an adsorbent was investigated. The nanocomposite was characterised using a series of analytical methods, including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. The effects of contact time, pH, adsorbent amount, and temperature parameters on adsorption were investigated. Various adsorption isotherm models were applied to interpret the equilibrium data in aqueous solutions; the compatibility of the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models with experimental data was examined. For a kinetic model consistent with experimental data, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion models were examined. The maximum adsorption capacity was calculated as 151.5 mg·g⁻¹ in the Langmuir isotherm model. The most suitable isotherm and kinetic models were the Freundlich and pseudo-second-order kinetic models, respectively. These results demonstrate the potential of the GO@Fe₃O₄@Pluronic-F68 nanocomposite as an adsorbent offering a sustainable solution for Ni(II) removal. Full article

Arsenic contamination in groundwater is a significant public health concern, with As(III) posing a greater and more challenging risk than As(V) due to its higher toxicity, mobility, and weaker adsorption affinity. Fe-Mn-based adsorbents offer a promising solution, simultaneously oxidizing As(III) to As(V), enhancing its adsorption. This study evaluates an Fe-Mn nanocomposite across typical batch (20 mg of adsorbent), fixed-bed column (28 g), and pilot-scale (2.5 kg) studies, bridging the gap between laboratory and real-world applications. Batch experiments yielded maximum adsorption capacities of 6.25 mg/g and 4.71 mg/g in a synthetic matrix and real groundwater, respectively, demonstrating the impact of the water matrix on adsorption. Operational constraints and competing anions led to a lower capacity in the pilot (0.551 mg/g). Good agreement was observed between the breakthrough curves in the pilot (breakthrough at 475 bed volumes) and the fixed-bed column studies (365–587 bed volumes) under similar empty bed contact times (EBCTs). The Thomas, Adams–Bohart, and Yoon–Nelson models demonstrated that lower flow rates and extended EBCTs significantly enhance arsenic removal efficiency, prolonging the operational lifespan. Our findings demonstrate the necessity of continuous-flow experiments using real contaminated water sources and the importance of optimizing flow conditions, EBCTs, and pre-treatment in order to successfully scale up Fe-Mn-based adsorbents for sustainable arsenic removal. Full article

Given the adverse effects of organic dyes from aqueous solutions on human physiology and the ecological system, establishing an effective system for their elimination is imperative. This study employs the in situ thermal (IST) method to synthesize nanocomposites comprising zeolitic imidazole frameworks, specifically Fe-ZIF-8 and Fe-ZIF-67. The investigation offers a comprehensive evaluation of the properties of these nano-adsorbents for the removal of malachite green (MG). The results indicate a significantly increased adsorption capacity of up to 495 and 552 mg g⁻¹ for Fe-ZIF-8 and Fe-ZIF-67, respectively. Furthermore, they demonstrate removal efficiencies of up to 90% and 95% for MG, respectively. Parameters associated with the adsorption process are derived from isotherms and removal kinetics, specifically the Freundlich model and the pseudo-second-order kinetics model, respectively. The enhanced adsorption capacity observed in Fe-ZIF-8 and Fe-ZIF-67 can be attributed to π–π stacking interactions, hydrogen bonding, and electrostatic attraction. After undergoing three cycles, both adsorbents consistently exhibit a high removal efficiency of approximately 85%, indicating notable structural integrity and outstanding potential for repeated use. The examined adsorbents display exceptional efficacy, favorable stability, and substantial specific surface area, underscoring their remarkable adsorption capabilities. The nanocomposites comprising Fe-ZIF-8 and Fe-ZIF-67 demonstrate considerable potential as highly favorable options for the elimination of MG and other cationic organic dyes from aqueous environments. Full article

In this study, an efficient and cost-effective nanocomposite material based on Opuntia ficus indica (cactus) powder modified with iron oxide nanoparticles was developed as an adsorbent for the removal of methylene blue (MB), a common water pollutant. The nanocomposite was synthesized through the co-precipitation method of Fe²⁺ and Fe³⁺ ions and characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and thermogravimetric analysis (TGA). Batch adsorption experiments were conducted over 24 h, varying different operational conditions, such as pH, temperature and initial pollutant concentration. Furthermore, a Box–Behnken design was employed to develop an empirical model for predicting removal efficiency and optimizing the adsorption conditions. The effects of adsorption variables including contact time (1–60 min), initial MB concentration (20–100 mg/L), pH (2–12), adsorbent dosage (2–6 g/L) and temperature (25–55 °C) on the removal capacity were examined. Under optimal conditions, the maximum removal efficiency of MB reached approximately 96%, with a maximum adsorption capacity of 174 mg/g, as predicted by the Langmuir model. The synthesized cactus/iron oxide nanocomposite demonstrated significant potential as an adsorbent for treating MB-contaminated water. Full article

Nowadays, there is an urgent need for efficient photocatalysts and adsorbents for environmentally relevant applications. This study investigates the effect of polyaniline (PANI) on the structure and performance of carbonized nanocomposites composed of PANI and TiO₂ nanotubes (NTs), focusing on their photocatalytic degradation efficiency and dye adsorption capacity. The hypothesis was that PANI forms conductive carbon domains and stabilizes the anatase phase during thermal treatment, enhancing the performance of TiO₂-NTs as photocatalysts. Nanocomposites based on PANI and TiO₂-NTs (TTP) were synthesized through chemical oxidative polymerization of aniline (ANI) in the presence of TiO₂-NTs using two TiO₂/ANI molar ratios of 50 and 150 and subsequently carbonized at 650 °C, yielding CTTP-50 and CTTP-150. The novel CTTP composites and carbonized pristine TiO₂-NTs (CTNT) were characterized by various techniques, including TEM, UV-Vis diffuse reflectance, Raman spectroscopy, XRD, and TGA. Their performance regarding dye adsorption and photocatalytic degradation under visible light was evaluated with Acid Orange 7, Methylene Blue, and Rhodamine B. CTTP-150 exhibited the highest adsorption capacity and photodegradation rate, attributed to the synergistic effect of PANI, which stabilizes the TiO₂ phase and enhances visible-light absorption and adsorption. Full article

Aerogels have gained much interest in the last decades due to their specific properties, such as high porosity, high surface area, and low density, which have caused them to be used in multiple and varied fields. As the applicability of aerogels is tightly correlated to their morpho-structural features, special consideration must be allocated to the fabrication method. An emerging technique for producing nanostructured materials with tailored morphology and dimensions is represented by continuous-flow microfluidics. In this context, this work explores the synergic combination of aerogel-based materials with microfluidic synthesis platforms to generate advanced nanocomposite adsorbents for water decontamination. Specifically, this study presents the novel synthesis of a magnetic silica-based aerogel using a custom-designed 3D microfluidic platform, offering enhanced control over nanoparticle incorporation and gelation compared to conventional sol–gel techniques. The resulting gel was further dried via supercritical CO₂ extraction to preserve its unique nanostructure. The multi-faceted physicochemical investigations (XRD, DLS, FT-IR, RAMAN, SEM, and TEM) confirmed the material’s uniform morphology, high porosity, and surface functionalization. The HR-MS FT-ICR analysis has also demonstrated the advanced material’s adsorption capacity for various pesticides, suggesting its adequacy for further environmental applications. An exceptional 93.7% extraction efficiency was registered for triazophos, underscoring the potential of microfluidic synthesis approaches in engineering advanced, eco-friendly adsorbent materials for water decontamination of relevant organic pollutants. Full article

Organic dyes are pollutants that threaten aquatic life and human health. These dyes are used in various industries; therefore, recent research focuses on the problem of their removal from wastewater. The aim of this study is to examine the clay/gum arabic nanocomposite (CG/NC) as an adsorbent to adsorb methylene blue (MB) and crystal violet (CV) dyes from synthetic wastewater. The CG/NC was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunaure–Emmett–Teller (BET). The effect of parameters that may influence the efficiency of removing MB and CV dyes was studied (dosage of CG/NC, contact time, pH values, initial concentration, and temperature), and the optimal conditions for removal were determined. Furthermore, an artificial neural network (ANN) model was adopted in this study. The results indicated that the adsorption behavior adhered to the Langmuir model and conformed to pseudo-second-order kinetics. The results also indicated that the removal efficiency reached 99%, and q_max reached 66.7 mg/g and 52.9 mg/g for MB and CV, respectively. Results also proved that CG/NC can be reused up to four times with high efficiency. The ANN models proved effective in predicting the process of the removal, with low mean squared errors (MSE = 1.824 and 1.001) and high correlation coefficients (R² = 0.945 and 0.952) for the MB and CV dyes, respectively. Full article

Micropollutants (MPs), which include both natural and manmade substances, are becoming more prevalent in aquatic habitats as a result of the insufficient removal of these compounds in wastewater treatment plants (WWTPs). Advanced remediation techniques are required due to their persistence and potential ecotoxicological hazards. Although adsorption and photo(electro)catalysis exhibit potential in laboratory-scale investigations, the effects of their use in actual WWTP systems are still poorly understood. However, before large-scale application can be implemented, a number of issues need to be resolved, including material limitations, reactor design and optimization, and actual wastewater complexities. This study critically evaluates the application of adsorption and photo(electro)catalysis to actual wastewater, as well as recent advancements in adsorption and photo(electro)catalytic systems for the removal of micropollutants. We also explore the particular difficulties and strategies involved in the large-scale use of adsorption and photo(electro)catalysis in the treatment of wastewater. Emerging trends such as nanocomposites, metal–organic frameworks (MOFs), heterojunctions, and single-atom catalysts (SACs) are highlighted by the bibliometric analysis. We also evaluate MPs’ ecological effects in aquatic environments and the incorporation of artificial intelligence (AI) for process optimization. A strategy for transferring nanotechnologies from laboratory-scale research to wastewater treatment implementation is presented in this paper. In this strategy, implementation is proposed based on actual wastewater conditions, focusing on the development of adsorbents and catalysts, reactor design and optimization, synergy between adsorption and catalysis, life cycle analysis, and cost–benefit studies. Full article

The synthesis of carbon-halloysite nanocomposites was carried out using aqueous sucrose solutions as a carbon precursor. Raw and calcined halloysite with different grain size classes were used as a carbon support. The influence of halloysite grain size and the calcination process on the carbon concentration in the composites and their adsorption characteristics towards the separation of naproxen from aqueous solutions was identified experimentally. The kinetic conditions of the process (pseudo-second-order kinetic model) indicate a favorable increase in the number of active sites formed after the deposition of the carbon layer on the surface of halloysite particles. Validation of the Langmuir multi-center isotherm adsorption model indicates a separation mechanism associated with the occurrence of multiple active centers on the nanocomposite adsorbent surface and the effect of separation without dissociation of naproxen particles. The obtained carbon-halloysite nanocomposite, due to the relatively cheap and simple, environmentally friendly production methodology and the required inexpensive raw materials, can be widely used in effective and common, economical treatment of wastewater streams from naproxen. The observed naproxen separation process effects are significant. Full article

The present study aims to prepare a composite via pyrolysis, based on sodium alginate (SA) and a natural clay collected from the eastern region of Morocco, specifically the OUJDA area (C.O.R), for use in the disposal process of emerging pharmaceuticals. The strategy of rapid microwave heating followed by nitrogen calcination at 500 °C was successfully applied to produce the pyrolyzed carbonaceous materials. The removal of paracetamol (PCT) by adsorption on the carbonaceous clay (ca-C.O.R) composite was investigated to determine the effect of operating parameters (initial contaminant concentration, contact time, pH, and temperature) on the efficiency of PCT removal. The nanocomposite was analyzed using various techniques, including the nitrogen gas adsorption–desorption isothermal curve, X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Three models were used to describe the kinetic adsorption, and it was found that the experimental kinetic data fit well with a pseudo-second-order kinetic model with a coefficient of determination R² close to one, a nonlinear chi-square value close to zero, and a reduced root mean square error RMSE (R² → 1, X² → 0 and lower RMSE). The adsorption was best described by the Sips isotherm. The ca-C.O.R composite achieved a PCT removal efficiency of 91% and a maximum adsorption capacity of 122 mg·g⁻¹ improving on the performance of previous work. Furthermore, the variation in enthalpy (∆H°), Gibbs free energy (∆G°), and entropy (∆S°) indicated that the adsorption is exothermic in nature. The composite has shown promising efficiency for the adsorption of PCT as a model of emergent pollutant from aqueous solutions, making it a viable option for industrial wastewater treatment. Using Density Functional Theory (DFT) along with the 6-31G (d) basis set, the geometric structure of the molecule was determined, and the properties were estimated by analyzing its boundary molecular orbitals. The adsorption energy of PCT on MMT and ca-C.O.R studied using the Monte Carlo (MC) simulation method was −120.3 and −292.5 (kcal·mol⁻¹), respectively, which shows the potential of the two adsorbents for the emerging product. Full article

A new voltammetric sensor (BDDE/Nafion@Fe₃O₄/BiF) was fabricated by applying a nanocomposite drop of Fe₃O₄ magnetic nanoparticles in Nafion onto the polished boron-doped diamond electrode (BDDE) surface. Then, after drying (5 min at room temperature), the electrode was electrochemically modified with bismuth film (BiF) during in situ analysis. The Nafion@Fe₃O₄/BiF modification of the BDDE contributes to the acquisition of the highest differential-pulse adsorptive stripping voltammetric (DPAdSV) signals of caffeine (CAF) due to the improvement of electron transfer and the increase in the number of active sites on which CAF can be adsorbed. The DPAdSV signals exhibited a linearly varied oxidation peak with the CAF concentration range between 0.5 and 10,000 nM, leading to the 0.043 and 0.14 nM detection and quantification limits, respectively. The practical applicability of the DPAdSV procedure using the BDDE/Nafion@Fe₃O₄/BiF was positively confirmed with commercially available energy drinks. Full article

The current work synthesizes and characterizes a new Fe₃O₄/SiO₂/PANI-SDBS nanocomposite designed as an efficient adsorbent for the removal of Cd²⁺ and Pb²⁺ ions from contaminated water. The process includes the polymerization of aniline on the Fe₃O₄/SiO₂ nanocomposite in the presence of SDBS. The Fe₃O₄/SiO₂/PANI-SDBS nanocomposite was characterized by using a variety of techniques, including FT-IR, XRD, TEM, SEM, BET, TGA, zeta potential measurements, and particle size distribution analysis, to evaluate its magnetic, structural, and surface properties. For the elimination of both Cd²⁺ and Pb²⁺ ions, ideal adsorption parameters were examined, including pH, adsorbent dose, and contact duration. The solution medium’s optimal pH for achieving the highest effectiveness of elimination for both metal ions was decided to be 7.0. The Fe₃O₄/SiO₂/PANI-SDBS adsorbent demonstrated high adsorption capacities for both Pb²⁺ (72.20 mg g⁻¹) and Cd²⁺ (67.84 mg g⁻¹) at pH 7, with corresponding removal efficiencies of over 94.10% and 77.47%, respectively. This efficiency is attributed to the composite’s large specific surface area and the strong binding affinity of its PANI and SDBS functional groups toward heavy metal ions. Multilayer adsorption on heterogeneous surfaces was shown by isotherm analysis that matched the Freundlich model and adsorption kinetic investigations that showed strong conformance with pseudo-second order for both metal ions. The thermodynamic study proves endothermic and spontaneous process for the removal of metal ions. Furthermore, the adsorbent may be readily recovered from solution thanks to the magnetic core, and regeneration by acid treatment enables reusability with consistent adsorption efficiency across several cycles, making it a cost-effective and sustainable option for continuous water purification processes. Its high adsorption capacity and reusability also make it suitable for use in emergency-response situations, such as the rapid cleanup of wastewater. Full article

This study investigated the enhanced adsorption capacity of a silver nanoparticle (AgNPs)-incorporated tamarind seed activated carbon nanocomposite (Ag/TSAC) for the elimination of methyl orange (MO) from aqueous solutions. The nanocomposite was analyzed using TGA, SEM, FTIR, and BET, revealing a mesoporous structure with a surface area of 54.92 m²/g. The results showed that the structure of tamarind seeds altered during pyrolysis, as shown by the loss of many functional groups and a weight decrease of 66.61% in the nanocomposite. The efficiency of the nanocomposite in eliminating MO was assessed by batch adsorption studies, which also examined the effects of solution pH, starting MO concentration, and nanocomposite dose. The best MO removal was seen at pH 2, indicating a positive electrostatic interaction between the dye and adsorbent. The results demonstrated that the Ag/TSAC nanocomposite significantly enhanced MO removal efficiency from 19% to 96% under optimal adsorptive conditions, due to the synergistic effect of the high surface area of activated carbon and the enhanced adsorption sites provided by the AgNPs. The study demonstrates the potential of Ag/activated carbon nanocomposite as a sustainable adsorbent for removing MO dye from wastewater using a second-order model and Langmuir model. Full article

Chromium-containing wastewater poses severe threats to ecosystems and human health due to the high toxicity of hexavalent chromium (Cr(VI)). Although iron oxide nanoparticles (IONPs) show promise for Cr(VI) removal, their practical application is hindered by challenges in recovery and reuse. Herein, a novel three-dimensional porous nanocomposite, Artemia cyst shell biochar-supported iron oxide nanoparticles (ACSC@ IONP), was synthesized via synchronous pyrolysis of Fe³⁺-impregnated Artemia cyst shells (ACSs) and in situ reduction of iron. The optimized composite C@Fe-3, prepared with 1 mol/L Fe³⁺ and pyrolyzed at 450 °C for 5 h, exhibited rapid removal equilibrium within 5–10 min for both Cr(VI) and total chromium (Cr(total)), attributed to synergistic reduction of Cr(VI) to Cr(III) and adsorption of Cr(VI) and Cr(III). The maximum Cr(total) adsorption capacity was 110.1 mg/g at pH 2, as determined by the Sips isothermal model for heterogeneous adsorption. Competitive experiments demonstrated robust selectivity for Cr(VI) removal even under a 64-fold excess of competing anions, with an interference order of SO₄²⁻ > NO₃⁻ > Cl⁻. Remarkably, C@Fe-3 retained 65% Cr(VI) removal efficiency after four adsorption–desorption cycles. This study provides a scalable and eco-friendly strategy for fabricating reusable adsorbents with dual functionality for chromium remediation. Full article

Dye wastewater poses significant risks to human health and aquatic ecosystems, necessitating efficient remediation strategies. This study developed a magnetic Fe₂O₃ nanocomposite (MNC) derived from phosphoric acid-treated walnut shell biomass carbon to remove Alizarin red S (AR) dye from polluted water. Characterization techniques confirmed the nanocomposite’s mesoporous structure, superparamagnetic properties (61.5 emu/g), and high crystallinity. Optimization using Response Surface Methodology (RSM) revealed a maximum adsorption efficiency of 94.04% under the following optimal conditions: A pH of 2, AR dye concentration of 85 mg/L, adsorbent dose of 1.5 g/L, and particle size of 448.1 nm. Adsorption followed pseudo-second-order (PSO) kinetics (R² = 0.9999) and Langmuir isotherm models (R² = 0.9983), with thermodynamic studies indicating spontaneous and endothermic chemisorption. The intra-particle diffusion model, Bangham, and Boyd plots describe the adsorption process, and external boundary layer diffusion of AR dye molecules in the aqueous phase limits the adsorbate removal rate. Regeneration tests demonstrated reusability over three cycles, with a desorption efficiency of 50.52% using 30 mM HCl. The MNC exhibited a maximum adsorption capacity (Q_max) of 115.35 mg/g, outperforming other adsorbents, making it an efficient and sustainable alternative solution for AR dye removal from water bodies. Full article