Adsorption of Methyl Red on Poly(diallyldimethylammonium) Chloride-Modified Clay

A novel, eco-friendly and cost-effective adsorbent, poly(diallyldimethylammonium) chloride (PDADMAC)-modified clay was developed to enhance its efficacy in removing Methyl Red (MR) from water. Different concentrations of PDADMAC solutions were evaluated during the synthesis and the effects of different operating conditions were investigated. The kinetic data closely followed the pseudo-first-order model, while equilibrium data were well described by Freundlich isotherm. MR removal efficiency decreased as solution pH or NaCl concentration increased, suggesting that electrostatic interaction plays a key role in the adsorption process. Regeneration studies using NaCl solutions revealed that a 1% NaCl solution effectively restored the adsorbent's capacity. The findings indicate that PDADMAC clay is a promising and sustainable adsorbent for MR removal. Additionally, a three-layer backpropagation artificial neural network (ANN) was developed to predict the MR removal efficiency based on the initial MR concentration, pH, NaCl concentration, and adsorption time. Among these variables, pH was identified as the most influential factor. This approach provides valuable insight into the outcome prediction of a given adsorption process.