ABSTRACT The co-sorption of vanadium and molybdenum was investigated using the ion exchange resin Purolite D3411, which contains multiple hydroxyl functional groups. Equilibrium batch, kinetic, dynamic column and desorption experiments were performed over a wide pH range (1.5–7.0) and with varying concentrations of competitive anions (Cl− and SO4 2−, 0–1000 mg.L−1). The maximum sorption capacities calculated from the Langmuir isotherms were 135 g.L−1 for vanadium and 105 g.L−1 for molybdenum. Optimal adsorption of both elements was achieved at pH = 4.5 in the presence of moderate concentrations of competitive anions, yielding a breakthrough capacity of approximately 40 g.L−1 for each ion. At pH values below 2.0 under zero or low concentrations of competing anions, and above 6.0 under high ionic competition, molybdenum adsorption remained relatively high (breakthrough capacities of 55 and 45 g.L−1, respectively), whereas vanadium adsorption was consistently low. In contrast, at pH = 4.5 and under high concentrations of competitive anions, vanadium exhibited good adsorption performance, while molybdenum adsorption was limited.

ABSTRACT In the existing biphasic protein precipitation methods, protein is precipitated and the water and solvent forms a single homogeneous phase. Thus, solvent recovery from aqueous solution is an additional step which is not needed in the present method. The novelty of the present method is that it is a single-step process wherein protein precipitation and solvent separation (acetonitrile, i.e. ACN) occurs simultaneously which would improve the overall efficiency of the process. A total of 88–90% (w/w) protein precipitation was achieved using three-phase sugaring out under the optimized conditions from simulated as well as actual dairy whey. Further, the phase ratio which is indicative of the solvent separation was 0.67 at the optimized conditions. Simultaneously, 72% (v/v) of the solvent was recovered. The quality of precipitated whey protein powder (WPP) was adjudicated by establishing the structural, nutritional, functional properties, in-vitro digestibility and antioxidant activity. The structure of the precipitated WPP was comparable with the commercial whey protein concentrate (CWPC). WPP showed good nutritional content. Emulsifying capacity and water holding capacity were equal to CWPC. In-vitro digestibility and antioxidant activity were also comparable with CWPC. Thus, the present method is highly efficient in protein precipitation and can become a novel alternative to conventional methods.

ABSTRACT In this study, styrene-butadiene rubber (SBR) and nitrile rubber (NBR) based hydrogels were synthesized by radical polymerization using ethylene glycol dimethacrylate (EGDMA) and 2,3-dimercaptopropanol crosslinkers. The hydrogel structure was değiştirfunctionalized by adding methacrylic acid (MA) and 2-hydroxyethyl methacrylate (HEMA) monomers in fixed ratios. The effects of crosslinker type and ratio on the swelling behavior, heavy metal adsorption capacity, and thermal properties of the hydrogels were systematically investigated.FTIR, XRD, SEM, and TGA analyses showed that the hydrogels were successfully synthesized and structurally stable. Swelling tests revealed that while the control hydrogels exhibited low swelling capacity (27.32% and 23.95%), Experiment 6 and Experiment 4 demonstrated superior performance with equilibrium swelling capacities of 98.22% and 93.17%, respectively. Heavy metal adsorption studies revealed that the hydrogels exhibited high selectivity, particularly toward As3+ ions; Experiments 6 and 4 achieved arsenic adsorption capacities of 9.91 mg/g and 9.97 mg/g, respectively. Thermogravimetric analyses showed that increasing the amount of crosslinking agents improved the thermal stability of the hydrogels.These results demonstrate that the developed hydrogels are strong candidates for environmental heavy metal removal applications.

ABSTRACT The discharge of Lead(II) ions (Pb2+) from bauxite mining effluents poses serious environmental and health risks, requiring cost-effective and sustainable treatment strategies. This study evaluates T. catappa leaf biomass as a low-cost biosorbent for Pb(II) removal from bauxite wastewater, quantified using Differential Pulse Adsorptive Stripping Voltammetry (DPAdSV). The biosorbent was prepared through drying, grinding, and chemical activation (100–150 µm). FTIR analysis confirmed hydroxyl, carboxyl, carbonyl, nitrogen, and polysaccharide groups involved in Pb(II) binding. Batch experiments showed an optimum pH of 5.0 and equilibrium at 24 h. At 120 mg L−1 initial concentration and 0.15 g L−1 dosage, adsorption reached 88.29 mg L−1. Langmuir modeling indicated a maximum capacity of 2.2 mg g−1 (R2 = 0.98), suggesting monolayer adsorption, while kinetics followed the pseudo-second-order model, indicating chemisorption. In fixed-bed columns (0.5–1.5 cm; 3 mL min−1), breakthrough time increased with bed height, and the Thomas model best described the data (32.11 mg g−1). Treatment of real wastewater spiked with 25 mg L−1 Pb(II) achieved >70% removal despite competing ions. Regeneration with 0.5 M HCl enabled >85% desorption and >70% efficiency after three cycles. These results demonstrate the potential of T. catappa biomass as an eco-friendly and reusable biosorbent.

ABSTRACT This study introduces cellulose acetate nanoparticles (CANPs) as an eco-friendly adsorbent for JG, synthesized in situ using the nanoprecipitation technique. The proposed mechanism consists of the formation of a cellulose acetate thin film upon the injection of the organic phase, followed by the rapid formation of spherical particles that entrap the dye solution. DLS analysis confirmed the successful formation of CANPs with a Z-average hydrodynamic diameter of 128.6 nm. The particle size distribution using the TEM technique was 93 ± 22 nm. The specific surface area, average pore diameter, and total pore volume of the CANPs were 1.141 m2 g−1, 28.7 nm, and 0.0082 cm3 g−1, respectively. The pHpzc of the CANPs was determined to be 6.2. The results showed that surface adsorption, upon aging the spherical particles, does not contribute significantly to the overall removal efficiency. Therefore, physical occlusion accounts for the observed high removal efficiency. Key parameters, pH, temperature, adsorbent dosage, and contact time, were optimized, with pH 8.0 at 20°C and a 15 min contact time yielding a maximum adsorption capacity of 52.64 mg g−1. Kinetic and isotherm studies suggest a pseudo-second-order model and Langmuir isotherm, indicating monolayer adsorption. Thermodynamic analysis confirms the process is exothermic and spontaneous.

ABSTRACT Tubular Axial Vortex Separator (TAVS) utilizes a high-speed rotating impeller to create a strong swirling flow for oil-water separation, boasting a single-tube capacity of 10,000 m3/d. It is anticipated to streamline oilfield produced water treatment and reduce carbon emissions. However, prototype tests have revealed that increasing the impeller’s speed does not consistently enhance separation efficiency. To investigate the decline mechanism and establish operational limits, a visualized TAVS test platform was constructed. High-speed cameras recorded oil core deformations, while FFT analysis studied its oscillation. Results showed separation efficiency peaks at 90.4% (water outlet oil droplet size: 55 μm) at 1000 rpm, stable up to 1500 rpm (droplet size rises to 90 μm). However, as rotational speed rises from 2500 to 4000 rpm, efficiency drops significantly (87% to 74.1%), mainly due to enhanced entrainment of large droplets. Above 3500 rpm, the oil core’s radial acceleration is 76.6% of centrifugal acceleration, and its oscillating area nears the oil outlet (A o/A out ≈0.85), causing oil discharge through the water outlet. Additionally, FFT confirms the oscillation frequency is directly tied to impeller speed, identifying it as the root cause. Field data corroborates the 1000 rpm optimum, aligning with experiments to support TAVS speed optimization.

ABSTRACT Heavy metals (HMs) are regarded as a significant environmental concern and are increasingly recognized as one of the most pressing environmental issues. These metals influence the air, soil, and groundwater and pose significant risks to living organisms particularly humans once they enter the food chain. Chemical precipitation, ion exchange, membrane separation, and electrochemical processes are a few conventional treatment methods that frequently have issues with cost, energy consumption, secondary pollution, and process inefficiency under challenging operating conditions. Because of its ease of use, affordability, and high removal efficiency, adsorption has become one of the most promising remediation techniques. Artificial intelligence (AI), especially artificial neural networks (ANNs), has drawn a lot of interest lately as a potent modeling and optimization tool for forecasting and improving heavy metal removal procedures. The removal of heavy metals from aquatic systems using ANN-based modeling techniques is thoroughly and critically evaluated in this paper. Training methods, performance evaluation measures, and the foundations of AI and ANN structures are all methodically covered. The use of ANN models to forecast the principal hazardous metals’ adsorption behavior with different adsorbents is examined critically and compared with conventional statistical and mechanistic models.

ABSTRACT Amino-rich anionic mesoporous silica (AAMS) nanoparticles were synthesized using a binary Co-Structure Directing Agent (CSDA) strategy to enhance nitrogen incorporation while preserving mesostructural order for U(VI) adsorption. All synthesized materials were comprehensively characterized using TEM, N2-sorption analysis, FTIR, XPS, zeta – pH measurements, and nitrogen elemental analysis. The binary-CSDA APTMS/APTES material exhibited a distinctive sea-shell-like morphology, providing enhanced surface accessibility, well-defined mesopore exposure, and improved diffusion, thereby contributing to its superior adsorption performance. Compared to the single-CSDA sample (surface area 503.6 m2 g−1, pore volume 0.866 cm3 g−1, nitrogen content 1.61 wt%, capacity 30 mg g−1), the binary systems combining APTES (3-aminopropyltriethoxysilane) with APTMS (3-aminopropyltrimethoxysilane) or N3TPED (N-[3-(trimethoxysilyl)propyl]ethylenediamine) achieved higher nitrogen contents (2.82–3.25 wt%), while maintaining high surface areas (394.7–336.6 m2 g−1) and uniform pore sizes (~3.8 nm). As a result, their U(VI) adsorption capacities increased significantly to 80 mg g−1 (APTES/APTMS) and 116 mg g−1 (APTES/N3TPED). These capacities surpass those reported for recent amino-based silica adsorbents, such as amide/phosphorus functionalized silica (95 mg g-1), amidoxime-modified mesoporous silica (~57 mg g-1), and amino-functionalized hydroxylated SBA-15 (115 mg g−1). Adsorption kinetics followed the pseudo-second order model (R2 ≈0.99), and the uptake mechanism was governed primarily by electrostatic attraction and physical interactions between protonated amino groups and hydrolyzed U(VI) species. Thermodynamic parameters (ΔG° = –3 to −5 kJ mol−1; ΔH° = –15 to −23 kJ mol−1) confirmed a spontaneous, exothermic process, while the materials maintained ≥80% regeneration efficiency after seven cycles. Owing to their high amino density, surface charge, and stable mesoporous architecture, the binary CSDA-derived AAMS nanoparticles also show strong potential for the removal of other wastewater pollutants, including heavy metals, pesticides, and pharmaceutical contaminants.

ABSTRACT Copper (Cu2+) contamination in industrial wastewater poses serious environmental and public health risks, especially in water-scarce countries such as South Africa. Concurrently, large quantities of apple pomace, an agro-industrial by-product, are generated annually and commonly disposed of by landfilling or incineration, creating additional environmental concerns. This study evaluates apple pomace as a low-cost, sustainable biosorbent for the removal of Cu2+ ions from wastewater. Response Surface Methodology (RSM), using central composite design, optimized initial Cu2+ concentration, adsorbent dosage, and particle size under two scenarios in Design-Expert 13. In the first scenario, targeting maximum overall removal, the optimal conditions were 14.47 mg/L Cu2+, 0.57 g of adsorbent, and a particle size of 125 µm, achieving 89.39% removal. In the second scenario, with 50 mg/L Cu2+, a 1 g dosage, and a particle size of 75 µm, 83.43% removal was achieved. Adsorption equilibrium followed the Langmuir isotherm (R2 = 0.984), and the Elovich model best described the kinetics. FT-IR and SEM-EDX analyses confirmed the presence of active functional groups, a porous surface morphology, and an elemental composition favorable for Cu2+ uptake. The findings demonstrate the potential of apple pomace for sustainable wastewater treatment, with future work focusing on regeneration, multi-metal systems, and fixed-bed applications.

ABSTRACT An integrated in situ advanced anaerobic digestion (AAD) process was developed at mesophilic temperatures using zero-valent iron (ZVI), papain, and cellulase to enhance digestion efficiency. Using Response Surface Methodology (RSM), the doses of three additives – zero-valent iron (ZVI), papain, and cellulase – were systematically optimized to maximize the removal efficiencies of five antibiotics and twelve antibiotic resistance genes (ARGs). The study analyzed correlations among antibiotics, ARGs, microbial community shifts, and biogas production, showing significant changes in methane production and microbial diversity. Except for OFL, all antibiotics were effectively removed from sludge, with SMZ, SMR, TC, and ROX removal rates reaching 93.59%, 78.93%, 51.38%, and 52.06%, respectively The RSM model identified the optimal experimental conditions as: ZVI 1063 mg/L, cellulase 23 mg/gSS, and papain 24 mg/gSS, which were validated experimentally at the antibiotics added 20 μg/L achieved from the response surface methods. The removal of ARGs varied, with intl1, tetA and sul2 being more persistent, while other ARGs had removal rates of 44.45%–96.91%. Dominant archaeal phyla in combined in situ AAD were Halobacterota and Euryarchaeota, with Methanomethylovorans as the main methanogen. Microbial community changes due to biological enzymes and ZVI enhanced antibiotic removal, while ARG removal depended on the fate of their potential hosts.