Adsorptive elimination of methylene blue dye from aqueous solution by chitosan‐nSiO₂ nanocomposite: Adsorption and desorption study, scale‐up design, statistical, and genetic algorithm modeling

Abstract

Heavy metals and organic dyes in water in concentrations exceeding the tolerable limit are unsafe for aquatic life and humans. Chitosan nanocomposites show a potential adsorption capacity to organic dyes. The present study encompasses the preparation of chitosan‐nSiO2 nanocomposites (CSNC) with different weight ratios of chitosan to nSiO2 and its application in the methylene blue (MB) dye adsorption. The nanocomposites were characterized with the help of SEM, BET, FTIR, XRD, and TGA. The adsorption experimentation was executed in batch mode under varying experimental conditions. Several isotherm and kinetic models were analyzed with the experimental data, and thermodynamic conditions required for adsorption were also determined. Maximum Langmuir adsorption capacities (qL) of the adsorbents for MB varied in the range of 21.32–31.34 mg g−1. The pseudo‐second‐order model was the best‐fitted kinetic model concerning all three adsorbents. The statistical modeling using multiple polynomial regression (MPR) for CWS CSNC1‐1 and CSNC2‐1 yielded the equations with R‐square ranging from 0.984 to 0.996. For GA modeling, it is more than 0.999. So, the efficient employment of statistical modeling, and genetic algorithms has also been achieved.

Chitosan‐nTiO2 Nanocomposite Synthesis and its Adsorptive Removal Capacity for Methylene Blue from its Aqueous Solution: Batch Adsorption Study and Modeling

“…With increasing concentration of MB, the percentage removal decreases due to lower accessibility of binding adsorptive sites. Due to the saturation of the binding sites, some MB cations remained unadsorbed at higher MB concentrations [24,44, 45] . The highest removal of MB was 77 % by CTNC1‐1, 74 % by CTNC2‐1, and 64.8 % by CWT at an MB concentration of 10 mgL −1 , and it was chosen as the optimal initial dye concentration.…”

“…[16][17][18][19][20][21] However, the limited solubility in acidic solution and the nonporous feature of CS are its significant shortcomings, so it needs chemical modification. [22][23][24] With the innovation of nanotechnology, different CS-metal oxide nanobio composites are designed by a range of nano-metal-oxides (nMOs), and their adsorptive suitability for organics is checked. [5,[25][26][27][28][29] TiO 2 nanoparticles are widely used in wastewater treatment due to their mechanical, physicochemical, and photocatalytic properties, thermal stability, and biocompatibility.…”

“…It is stable, reactive, biocompatible, biodegradable, and has chelation behaviour, making it a bio‐sorbent [16–21] . However, the limited solubility in acidic solution and the nonporous feature of CS are its significant shortcomings, so it needs chemical modification [22–24] . With the innovation of nanotechnology, different CS‐metal oxide nano‐bio composites are designed by a range of nano‐metal‐oxides ( n MOs), and their adsorptive suitability for organics is checked [5,25–29] …”