Preparation And Characterisation Of Integrated Bioadsorbent Chitosan/Hydroxyapatite/Rice Straw From Byproducts For Heavy Metals Removal In Water Treatment

Abstract

The prevention and control of water pollution caused by heavy metals are of great emphasis due to its hazardous effect to the living organism. The revalorization of biowaste materials has led to the main objective of this study; to produce bio- adsorbent from agriculture (rice straw) and marine (hydroxyapatite, HAP) for heavy metal removal in water treatment. In order to produce a high affinity bio-adsorbent heavy metal ion, the surface of alkaline rice straw powders (RSA) was modified by integration with chitosan (CH), hydroxyapatite (HAP), and stabilizing agent (sodium hydroxide, NaOH). Firstly, HAP was synthesized from the bulk seashell via calcination at 1000°C followed by wet precipitation at different reaction times (3, 5, 24, 48, and 72 h). The bio-adsorbent (capable of removing 99.1% of Pb2+) was produced at the reaction time of 48 h (HAP48). In the second stage of the study, equivalent ratios of HAP48 and CH at various composition percentages (5%, 15%, 25%, 35%, and 45%) were mixed prior to incorporation with 3 g of RSA to evaluate its removal capability towards selected heavy metal ions.