Nanocomposites of natural bone that show some benefits in terms of both composition and microstructure were synthesized by an in situ precipitation method. Hydroxyapatite (Hap) was prepared from cost-effective precursors within chitosan (CS) dissolved in aqueous acetic acid solution. The nanocomposite was synthesized for the removal of brilliant green dye (BG) from a contaminated water solution. The compositional and morphological properties of the nanocomposite were studied by means of FTIR spectroscopy, X-ray diffraction (XRD), SEM, and TEM analysis. Batch experiments were carried out to investigate the effects of pH, contact time, and initial concentration, as well as the adsorbent dosage and zero point charge for the sorbent to determine a suitable medium for the adsorption process. The sorption models using Mories-Weber, Lagrange, and Bangham equations were used to identify the mechanism and reaction order. The isotherm model was carried out using Langmuir, Freundlich, and Dubinin-Radusekevisch-Kanager equations to calculate the adsorption capacity and type of adsorption. Thermodynamic parameters, enthalpy change (∆Ho), entropy change (∆So), and Gibbs free energy (∆Go) were evaluated. All of the results suggest the feasibility of using nanocomposites as a sorbent for brilliant green dye removal.
The present study aims to investigate the adsorption behavior of Cu(II) and Cd(II) ions from wastewater onto low-cost adsorbents either raw date pits (RDP), cheap agricultural and nontoxic materials, or chemically activated carbon (ADP) prepared by modified date pits using phosphoric acid. A series of experiments were conducted in a batch system to evaluate the effect of system variables. The adsorption process is affected by various parameters such as solution pH, contact time, initial concentrations of metals, and adsorbent dose. The optimum pH required for maximum adsorption was found to be 5.8 ± 0.5. The experimental data were tested using Langmuir, Freundlich, Dubinin-Radushkevich (D-R) isotherm equations. It was observed that the adsorption capacity of date pits increased after treatment with phosphoric acid. The maximum uptake capacities (Q m ) were 7.40 and 33.44 mg copper(II) per gram of RDP and ADP, respectively, while 6.02 and 17.24 mg cadmium(II) per gram of RDP and ADP, respectively. The results showed that although the equilibrium data could be described by the three models used, Langmuir model gave slightly better results while Freundlich model gave better results when using raw and activated date pits.
Substantial improvement is needed in efficient and affordable decolorization and disinfection methods to solve the issues caused by dyes and harmful bacteria in water and wastewater. This work involves the photocatalytic degradation of methylene blue (MB) as well as gram-negative and gram-positive bacteria by cobalt-doped tin oxide (Co-SnO2) nanoparticles (NPs) and Co-SnO2/SGCN (sulfur-doped graphitic carbon nitride) nanocomposites (NCs) under sunlight. The coprecipitation approach was used to synthesize the photocatalysts. Maximum methylene blue (MB) photocatalytic degradation was seen with the 7% Co-SnO2 NPs compared to other (1, 3, 5, and 9 wt.%) Co-SnO2 NPs. The 7% Co-SnO2 NPs were then homogenized with different amounts (10, 30, 50, and 70 weight %) of sulfur-doped graphitic carbon nitride (SGCN) to develop Co-SnO2/SGCN heterostructures with the most significant degree of MB degradation. The synthesized samples were identified by modern characterization methods such as FT-IR, SEM, EDX, UV-visible, and XRD spectroscopies. The Co-SnO2/50% SGCN composites showed a significant increase in MB degradation and degraded 96% of MB after 150 min of sunlight irradiation. Both gram-negative (E. coli) and gram-positive (B. subtiles) bacterial strains were subjected to antibacterial activity. All samples were shown to have vigorous antibacterial activity against gram-positive and gram-negative bacteria, but the Co-SnO2/50% SGCNcomposites exhibited the maximum bactericidal action. Thus, the proposed NC is an efficient organic/inorganic photocatalyst that is recyclable and stable without lowering efficiency. Hence, Co-SnO2/50% SGCNNC has the potential to be employed in water treatment as a dual-functional material that simultaneously removes organic pollutants and eradicates bacteria.
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