Research on the adsorption of Pb2+ ions and methylene blue dyes by a kapok and polypropylene fibre web

Abstract

Purpose This study aims to investigate into the adsorption mechanism of heavy metal ions Pb2+ and methylene blue (MB) dyes on an adsorbent-web formed from kapok fibres (KP) and polypropylene fibres (PP). Design/methodology/approach Initially, the KP underwent pre-treatment with NaClO2 solution, and their morphology and structure changes were examined through scanning electron microscope images. Subsequently, the KP fibres were blended with PP fibres at a ratio of 70 / 30 and processed through a laboratory carding machine to form a fibre web, which was then secured using a heat press to fabricate the adsorbent-web. The resultant adsorbent-web was subjected to evaluation for the adsorption process. Findings The findings revealed that the adsorbent-web produced via the dry-laid method exhibited promising attributes, and the adsorption process conformed to the pseudo-second-order model and the Langmuir isotherm model. Parameters such as adsorbent-web porosity, solution pH, and adsorption thermodynamics exerted notable influences on the adsorption capacity of the adsorbent-web. Notably, the adsorbent-web demonstrated remarkable reusability and desorption capacity. In the fifth cycle, the adsorption capacity of adsorbent-web for MB and Pb2+ ions only decreased by 9.13% and 11.48%, respectively, compared to the first cycle. The desorption efficiency of the adsorbent-web exceeded 90% for MB and over 73% for Pb2+ ions. Originality/value This study makes a significant contribution to the practical application of KP as an adsorbent-web for treating waste from the textile dyeing industry.