Lead Removal from Water Using CTAB-Enhanced Nanosilica-Coated Sand Barrier Under Continuous Flow: Experimental Study and Breakthrough Curve Modelling

Abstract

This study presents the development of a novel permeable reactive barrier (PRB) material for lead removal from contaminated water using nanosilica-coated sand enhanced with cetyltrimethylammonium bromide (CTAB). The synthesis process involves coating quartz sand with nanosilica particles in the presence of CTAB to improve the dispersion and binding of the nanoparticles. Continuous fixed-bed column experiments were conducted for up to 27 days to evaluate the performance of the modified media under different flow rates (5 and 15 milliliters per minute) with an initial lead concentration of 50 milligrams per liter. The breakthrough curves obtained were analyzed using several empirical models, including Bohart-Adams, Thomas-BDST, Belter-Cussler-Hu, Clark, and Yan models. The experimental data showed a strong aggreement to the Thomas-BDST and Clark models, indicating pseudo-second-order kinetics and multilayer adsorption mechanisms. The coated media demonstrated stable hydraulic conductivity of approximately 2.5 x 10-2 centimeters per second throughout the operation, maintaining adequate permeability for continuous flow conditions. The findings suggest that the CTAB-enhanced nanosilica-coated sand represents a promising, cost-effective, and scalable solution for the in-situ remediation of lead-contaminated groundwater through PRB technology.