The study of non-linear kinetics and adsorption isotherm models for Acid Red 18 from aqueous solutions by magnetite nanoparticles and magnetite nanoparticles modified by sodium alginate

Abstract

Azo dyes are widely used in various industries. These substances produce toxic byproducts in aquatic environments in addition to their mutagenic and carcinogenic potential effects. In this study, the effect of magnetite nanoparticles and magnetite nanoparticles modified by sodium alginate in batch systems and nonlinear kinetic and adsorption isotherm models were investigated. Magnetite nanoparticles were synthesized by chemical co-precipitation method and then modified and used as adsorbent to adsorb Acid Red 18. After determining the optimum pH and adsorbent dose, non-equilibrium models for kinetic adsorption were tested with concentrations (25-100 mg/L) and at eight different periods of time (1-15 min) and the pseudo-first-order and pseudo-second-order non-linear models were used to describe the results. For adsorption isotherm, a contact time of 120 min was studied in different concentrations (25-100 mg/L) and the residual concentration of Acid Red 18 was obtained. The results are described by non-linear Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The optimum amounts of pH for magnetite nanoparticles and for modified ones were 3 and 5, respectively, the efficiencies were 0.75 and 0.2 g/L, respectively. According to the results sodium alginate has a high performance in adsorption of Acid Red 18. Adjusted correlation coefficients and chi-square test showed that Freundlich isotherm and then Langmuir isotherm can well describe the experimental results. In Freundlich, the value of (Kf) was 3.231 (L/g) for magnetite nanoparticles and 21.615 (L/g) for modified adsorbent. In Langmuir, the value of (qm) was 16.259 (mg/g) for magnetite nanoparticles and 73.464 (mg/g) for modified adsorbent. Comparing the Langmuir maximum calculated adsorption capacity indicated that modified adsorbent can adsorb the pollutants 6.5 times more than the other one.

PVA/TEOS crosslinked membranes incorporating zinc oxide nanoparticles and sodium alginate to improve reverse osmosis performance for desalination

“…NaAlg is a negatively charged biodegradable polysaccharide that is extracted from brown seaweed. The phenomenal properties of the low‐cost NaAlg are biocompatibility, nontoxicity, and its biological origin . To generate antimicrobial properties in blended polymer solutions, the incorporation of metallic nanoparticles is required, such as silver nanoparticles (Ag‐NPs) and ZnO‐NPs .…”

“…The phenomenal properties of the low-cost NaAlg are biocompatibility, nontoxicity, and its biological origin. [19][20][21] To generate antimicrobial properties in blended polymer solutions, the incorporation of metallic nanoparticles is required, such as silver nanoparticles (Ag-NPs) and ZnO-NPs. [22][23][24][25] The ZnO-NPs metallic nanoparticles enhance water permeability, antibacterial activity, and metal uptake capacity.…”

Statistical analyses on effective removal of cadmium and hexavalent chromium ions by multiwall carbon nanotubes (MWCNTs)

“…The result clearly showed that Langmuir isotherm amongst the other isotherms studied, best described the adsorption of Cd(II) and Cr(VI) ions with higher correla-tioncoefficientR 2 (>0.99), followed by Dubinin-Radushkevich, Temkin, and Freundlich model, respectively. In addition, this assertion was further justified with lower values of chi-square (χ 2 ), the sum of square error (ERRSQ/SSE), and the sum of absolute error (EABS), obtained when compared with the order models indicating the closeness of the model experimental results to the calculated results obtained [36,37,38]. This finding is similar to the results obtained on the sorption of cadmium and hexavalent chromium from electroplating wastewater [23] and non-linear prediction of kinetic and equilibrium data for the adsorption of hexavalent chromium by carbon materials [39].…”

Synthesis of a functional biomass lignin-based hydrogel with high swelling and adsorption of Acid Red 73

“…∆S<0, it shown that the adsorption process was a process of decreasing entropy. Studies have shown (Berizi et al 2016;Mao et al 2018) that when the absolute value of ∆G is less than 20 kJ•mol -1 , the adsorption is physical adsorption; when the absolute value of ∆H is within the range of 2~29kJ/moL, the force between the adsorbent and the solute is dominated by hydrogen bonding. It can be seen from Table 5 that the absolute value of ∆G during the adsorption process of the LAD hydrogel adsorbent on AR 73 was 4.494～6.247 kJ•moL -1 , and the absolute value of ∆H was 23.640 kJ•moL -1 .It shown that there was hydrogen bond in the adsorption process of LAD on AR 73 in addition to physical adsorption.…”