Chitosan–Resole–Pectin Aerogel in Methylene Blue Removal: Modeling and Optimization Using an Artificial Neuron Network

Abstract

In this study, a novel chitosan–resole–pectin aerogel (CS–R–P) was created from a sol–gel reaction with a solution of Cs and P with resole by a freeze-drying technique, and this adsorbent was proposed for the removal of methylene blue (MB). In addition, with the use of an artificial intelligence technique known as an artificial neural network (ANN), this material was modeled and optimized. Its physical morphology and chemical composition were also characterized with FTIR and XPS, and its adsorption properties were analyzed. For modeling the adsorption process, three main parameters were used: the chitosan–resole–pectin concentration (45–75%), thermal treatment (6–36 h), and known concentrations of methylene blue (25–50 and 100 mg/L), established on the Box–Behnken design. The ANN was coupled with the improved gray wolf optimization (IWGO) metaheuristic algorithm, achieving a correlation coefficient of R2 = 0.99. The characterization indicates that the surface of the aerogels was micro- and mesoporous, the resole gave physical stability, and the polysaccharide base delivered the functional groups necessary for dye adsorption; the aerogels were successful dye adsorbents with a qe of 12.44 mg/g. Finally, the physical and chemical sorption was ascertainable with an adsorption that followed pseudo-second-order kinetics. The MB adsorption was clearly occurring though cation exchange and hydrogen binding as observed in the chemical composition. The ANN with the gray wolf optimizer was used for the prediction of the best operating parameters for MB removal, applying the following conditions—the CS–R–P aerogel concentration (52/30/18), the thermal treatment (9.12 h), and the initial concentration of methylene blue (37 mg/L)—achieving a 94.6% removal. These conclusions suggest that using artificial intelligence such as an ANN can provide an efficient and practical model for maximizing the removal action of new aerogels based on chitosan.

A novel approach for adsorption of organic dyes from aqueous solutions using a sodium alginate/titanium dioxide nanowire doped with zirconium cryogel beads

“…Organic dyes used in the printing industries and dyeing are accompanied by their presence in wastewater harmful to human health and biota. Indeed, these coloring molecules minimized the transparency and esthetic value of water, which reduces light penetration, thus affecting photosynthesis ( Li et al, 2021 ), and raises the chemical oxygen demand (COD) ( Flores-Gómez et al, 2023 ), due to their extreme stability, making it difficult to break them down using light and oxidation reactions ( Somma et al, 2021 ). Additionally, these dyes are allergenic, carcinogenic, and non-degradable ( Laysandra et al, 2017 ).…”

“…Cryogel, a type of adsorbent, can prevent the technical issues associated with recovering powder adsorbents and secondary contamination. For examples, without being exhaustive: chitosan–resole–pectin aerogel ( Flores-Gómez et al, 2023 ), magnetic gel beads based on polyanetholesulfonic acid/alginate/magnetic zeolite ( Metin et al, 2020 ), K-carrageenan and alginate ( Ammar et al, 2021 ), chitosan ( Khnifira et al, 2021 ), magnetic nanoparticles of chitosan-glyoxal/ZnO/Fe₃O₄ crosslinked using a Schiff base ( Reghioua et al, 2021 ), fibrous composite foams chitosan/sodium alginate ( Zhao et al, 2020 ), calcium alginate-immobilized graphene oxide composites ( Li et al, 2013 ), MXene/PEI-functionalized sodium alginate ( Feng et al, 2021 ), and amino-functionalized sodium alginate ( Wang et al, 2022 ). The use of alginate more than other biopolymers is due to several considerations.…”