Adsorptive removal of naproxen onto nano magnesium oxide-modified castor wood biochar: Treatment of pharmaceutical wastewater via sequential Fenton's-adsorption process.

This current investigation explored the thermal conversion process of castor wood into biochar, which was subsequently harnessed for removing naproxen from pharmaceutical industrial effluent via adsorption. Surface composition analyses conducted through scanning electron microscopy-energy dispersive X-ray, laser-induced breakdown spectroscopy, and Fourier-transform infrared studies unveiled the presence of nano MgO particles within the adsorbent material. Employing optimization techniques such as response surface methodology facilitated a refined approach to batch study. The optimized conditions for batch naproxen sodium (NPX) adsorption on nano-MgO-modified biochar were identified as pH 4, 1.5 g/L adsorbent dosage, and a 120-min contact time maintaining a constant NPX concentration of 10 mg/L. The adsorption capacity was calculated to be 123.34 mg/g for a nano-magnesium oxide-modified castor wood biochar (modified biochar) and 99.874 mg/g for pristine castor wood biochar (pristine biochar). Fenton's reagents comprising 15 mM of FeSO4 (7H2O) and 25 mM of H2O2 have been scrutinized under conditions of pH 3.0, a reaction time of 30 min, a temperature of 30°C, and stirring at 120 rpm, followed by batch adsorption treatment. The COD, NH3-N, NO3 -, PO4 3-, and NPX removal percentages was found to be 90%, 87%, 79%, 80%, and 90%, respectively. Thus nano MgO-modified biochar holds promise of treatment of pharmaceutical effluent.

Response surface methodology-based optimisation of adsorption of diclofenac and treatment of pharmaceutical effluent using combined coagulation-adsorption onto nFe2O3 decorated water chestnut shells biochar.

This work involved the preparation of pristine and iron nanoparticle-loaded biochar from a water chestnut shell to remove diclofenac sodium (DCF) containing effluent of pharmaceutical origin. To create suitable forecasting equations for the modelling of the DCF adsorption onto the adsorbent, response surface methodology (RSM) was used. The parameters, e.g. pH, adsorbent mass, DCF concentration and contact time, were used for the modeling of adsorption. The RSM model predicts that for 98.0% DCF removal, the ideal conditions are pH 6, an adsorbent dose of 0.5 g L-1, and a contact time of 60 min with an initial adsorbate concentration of 25 mg L-1 at 303 K. The maximum capacity deduced from the Langmuir model was 75.9 mg g-1 for pristine water chestnut shell biochar (pWCBC) and 122.3 mg g-1 for magnetically modified nano-Fe2O3 biochar (mWCBC). Under equilibrium conditions, the Langmuir model was the best-suited model compared to the Temkin and Freundlich models. The adsorption data in this investigation efficiently fitted the pseudo-second-order model, emphasizing that chemisorption or ion exchange processes may be involved in the process. The WCBC demonstrated recyclability after 10 cycles of repeated adsorption and desorption of DCF. A combined coagulation adsorption process removed COD, NH3-N, NO3-, PO43-, and DCF by 92.50%, 86.41%, 77.57%, 84.54%, and 97.25%, respectively. This study therefore shows that coagulation followed by adsorption onto biochar can be a cost-effective substitute for conventional pharmaceutical wastewater treatment.

PSf Membrane-Impregnated Jute-Copper Nanocomposite as Highly Efficient Dye Removal Material.

Water pollution, driven by the discharge of dyes from industrial processes, poses a significant environmental and health hazard worldwide. Methylene blue, a common dye, constitutes particular concern due to its persistence and toxicity. Conventional wastewater treatment methods often struggle to effectively remove such contaminants. In this study, we introduce a novel approach utilizing a polysulfone-based composite membrane incorporating pretreated jute fibers and copper nanoparticles for the removal of methylene blue from aqueous solutions. The pretreated jute fibers undergo alkali and hydrogen peroxide treatments to enhance their adsorption capabilities, while copper nanoparticles are incorporated into the membrane to bolster its antimicrobial properties. Through comprehensive characterization techniques, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), and scanning electron microscopy (SEM), we confirm the structural and chemical properties of the composite membranes. Batch adsorption studies reveal the superior performance of the composite membrane compared with individual components. Specifically, at lower methylene blue concentrations (∼20 ppm), the composite membrane demonstrates a remarkable percent removal value of about 97%, while at higher concentrations (∼100 ppm), the percent removal remains substantial at 85%. Additionally, desorption studies elucidate the retention capacity of the adsorbed dye, indicating the feasibility of the composite membrane for practical applications in wastewater treatment. These findings underscore the potential of nanocomposite-fiber membranes as sustainable and cost-effective solutions for mitigating water pollution. By harnessing advancements in nanotechnology and materials science, the presented innovative composite membranes could offer promising avenues for addressing water pollution challenges and promoting environmental sustainability.

Cumulative human exposure and environmental occurrence of phthalate esters: A global perspective.

In the current investigation, the distribution and extent of human exposure of phthalate esters (PAEs) have been reported on global extent based on computed indices. The proposed indices were calculated based on environmental concentrations, toxicity, occurrence, environmental fate, and transport of PAEs. The cumulative phthalate exposure index (PEI) based on the phthalate pollution index (PPI) was mapped on a global scale based on the existing data reported in the literature. The results revealed that the PAEs are heterogeneously distributed globally, and about 30% of total environmental PAEs are ultimately exposed to the average human being. The comparative distribution of PAEs in various environmental compartments including urban-rural, indoor-outdoor, home-dormitory-classroom, and their exposure likelihood were studied based on indices. More than 90% of total human exposure of PAEs was observed to be from indoor environmental compartments. Significantly high exposure was observed in the urban population as compared to the rural population. About 70% of the total phthalate pollution sub-index of dust was observed from home followed by a classroom of ∼15% and then a dormitory of ∼10%. In addition, the indices were equated with the current human development index (HDI), gross national income (GNI), and exposure of particulate matter of each country. Based on current findings, the population living in the areas where >20 µg/m3 of particulate matter has been reported are possibly exposed with higher PAEs. The indices were highly diversified at high HDI (0.9) values and between 40,000 and 50,000 $ per capita income due to different usage of phthalate-containing products, disposal, and extensive monitoring work carried out by the developed and developing countries.