Efficient adsorptive removal of paracetamol and thiazolyl blue from polluted water onto biosynthesized copper oxide nanoparticles

Insight into the wheat residues-derived adsorbents for the remediation of organic and inorganic aquatic contaminants: A review

Wheat is a major grain crop of the world that provides a stable food for human consumption. Large amounts of by-products/waste materials are produced after the harvesting and processing of wheat crop. Such materials can cause an environmental issue if not disposed of properly. Several studies have shown that wheat residues can be efficient precursors for adsorbents because of their availability, renewability, lignocellulosic composition, and surface active groups enriched structure. In the literature, there are few review articles that address wheat residues-based adsorbents. However, these reviews were specific in terms of adsorbate or adsorbent and did not provide detailed information about the modification, properties, and regeneration of these adsorbents. This article extensively reviews the utilization of wheat biomass/waste including straw, bran, husk, and stalk as precursors for raw or untreated, chemically treated, carbonaceous, and composite adsorbents against various environmental pollutants. The influences of inlet pollutant amount, adsorbent dose, pH, temperature, and time on the performance of adsorbents against pollutants were considered. The maximum uptakes, equilibrium time, and adsorption nature were identified from isotherms, kinetic, and thermodynamic studies. The highest adsorbed amounts of most tested contaminants were 448.20, 322.58, and 578.13 mg/g for lead, chromium, and copper, 1374.6 and 1449.4 mg/g for methylene blue and malachite green, and 854.75, 179.21, and 107.77 mg/g for tetracycline, phosphate, and nitrate, respectively. For the studied adsorbate/adsorbent systems the adsorption mechanism and regeneration were also discussed. Significant results and future directions are finally presented.

Ecologically sustainable removal of pharmaceuticals: A mechanistic study of bismuth sulfide-graphene oxide/silver nanocomposite

Bismuth sulfide nanoparticles (BiS NPs) were synthesized via the hydrothermal method, and reduced graphene oxide(rGO) and silver nanoparticles (Ag), which acted as substrates, have prepared using the chemical reduction method. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy, and photoluminescence spectroscopy. Commercially available paracetamol-500 mg (PAM) and aspirin-300 mg (ASP) were selected for photodegradation under visible light using the as-prepared composites in an aqueous solution. Photoluminescence spectroscopy was used to detect PAM and ASP using the photo-excited electron transfer (PET) process, and the limit of detection (LOD) has obtained for PAM(8.70 ppm) and ASP(4.43 ppm) with a sensitivity of 0.9954 and 0.8002, respectively. Fourier transform infrared spectroscopy (FTIR) was used to analyze the before and after degradation products and to confirm the disintegrated products such as -COOH and -CH- both before and after disintegration.. The experimental data were found to fit well with the Freundlich isotherm, suggesting that the as-prepared nanocomposites exhibited a heterogeneous nature for PAM (5119 mg/L), and the pseudo-first-order kinetic model suggests ASP (1030 mg/L) with R2 values of 0.9119 and 0.7075. The risk assessment analysis of PAM was 9.823 μg/L(RQ > 1) and that of ASP was 0.2106 μg/L(RQ < 1), indicating that PAM has a higher potential risk than ASP. The demographic data of the participants indicated that PAM was the most stockpiled medicine at home; this work also encompasses the action of a single PAM and ASP tablet toward the environment, if it is accidently disposed of improperly could create massive water/soil pollution; hence, the care/duty of each person should follow the proper disposal of medical waste because we cannot replace this environment.

Acid-activated corn silk as a promising phytosorbent for uptake of Malachite green and Cd (II) ion from simulated wastewater: equilibrium, kinetic and thermodynamic studies

Malachite green (MG) dye and cadmium metal ion are toxic pollutants that should be removed from aqueous environment. The recent study aimed to examine the adsorption behavior of MG dye and Cd (II) from wastewater onto low-cost adsorbent prepared by activating corn silk with nitric acid (ACS) and characterized by SEM, FTIR, XRD, BET and TGA. The optimum MG and Cd (II) adsorption was observed at pH 7 and pH 9 and maximum uptake of both pollutants was at 0.5 g dosage, 60 mins contact time and 20 mg/L initial concentration. The retention of dye and metal ion by the studied adsorbent was best fit to Langmuir isotherm and Pseudo-second order kinetics. The maximum monolayer coverage capacity of ACS for MG dye and Cd (II) ion was 18.38 mg/g and 25.53 mg/g, respectively. Thermodynamic studies predicted a spontaneous reaction with exothermic process for MG dye whereas an endothermic and spontaneous process was confirmed for Cd ion based on estimated parameters. The adsorption mechanism of MG dye and Cd (II) uptake was by combination of electrostatic interaction, pore diffusion, ion exchange, pie-pie attraction, hydrogen bonding, and complexation. The adsorbed pollutants were effectively desorbed with significant regeneration efficiency after successive five cycles that proved the potential of low-cost biosorbent for selective sequestration of cationic dye and divalent metal ion from effluents.

Synthesis and characterization of Alg/Gel/n-HAP/MNPs porous nanocomposite adsorbent for efficient water conservancy and removal of methylene blue in aqueous environments: Kinetic modeling and artificial neural network predictions

In this study, a new porous nanocomposite adsorbent for water conservancy was synthesized using the freeze-drying technique to adsorb a cationic dye (Methylene Blue) in an aqueous environment. The nanocomposite adsorbent was synthesized using natural polymers, gelatin, and sodium alginate, and hydroxyapatite and magnetic iron oxide nanoparticles was incorporated into the polymer network to improve mechanical properties and increase the surface-to-volume ratio. To confirm the structure and morphology of the sample, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM) techniques were employed. In addition, the magnetic properties of the synthesis of MNPs and porous nanocomposite were determined using value stream mapping (VSM) and dynamic light scattering (DLS). The adsorption of Methylene Blue (MB) was studied as a function of effective physical and variable parameters, such as time, temperature, pH, and initial concentration. The synthesized porous nanocomposite adsorbent exhibited a high adsorption capacity of 473.2 mg g-1 and followed pseudo-second-order kinetics. Additionally, the maximum adsorption capacity was observed at an initial concentration of 534.9 mg g-1. The adsorbent was also sensitive to temperature changes and was well-described thermodynamically and isothermally by the Freundlich isotherm model. Two artificial neural networks (ANNs) were also developed to investigate the properties of the synthesized nanocomposites. In the first ANN, the properties of the nanocomposites, including pore size, porosity, compressive strength, and elastic modulus, were predicted based on the variations in the weight percentages of gelatin and hydroxyapatite. In the second ANN, the effects of changes in temperature and initial concentration on the adsorption of MB by the synthesized nanocomposite samples were predicted. The ANNs' predictions indicated that increasing the weight percentage of hydroxyapatite nanoparticles and gelatin enhances the physical, mechanical, and adsorption performance of the synthesized porous nanocomposites. The best results were achieved for the sample containing 40 wt % of gelatin and 30 wt % of hydroxyapatite nanoparticles. Furthermore, the ANN models demonstrated that increasing the temperature and initial concentration resulted in an increase in the amount of MB adsorbed.

Graphene Oxide-Polyphenylsulfone Nanocomposite Beads for Paracetamol Removal from Aqueous Solution

This study introduces a promising and practical method for the removal of paracetamol from aqueous environments, employing graphene oxide-polymer nanocomposite beads. The approach involves the utilization of a straightforward and facile phase inversion method, offering a convenient and efficient one-step process for the creation of adsorbent beads by integrating polymers and graphene oxide (GO). The synthesized nanocomposite beads are tailored for the removal of paracetamol from simulated wastewater in batch systems. Extensive characterization techniques including XPS, FTIR, SEM, TGA, and zeta potential analysis are employed to scrutinize the chemical properties and structural attributes of the prepared beads. The investigation explores the impact of critical parameters such as adsorbent dosage, adsorption duration, initial paracetamol concentration, and solution pH on the adsorption process. These nanocomposite beads exhibit an exceptional paracetamol removal efficiency, achieving up to 99% removal. This research not only contributes to the advancement of efficient and sustainable adsorbent materials for pollutant removal but also underscores their potential for environmentally friendly and cost-effective solutions in the domain of wastewater treatment.