Cellulose Isolation from Cotton Gin Waste and Synthesis of Cellulose/PVA Membrane for Heavy Metals Removal

Abstract

The scope of this project was waste minimization through resource recovery and the targeted waste was Cotton Gin Waste (CGW). The process of cellulose isolation from cotton gin waste was optimized and a fibrous membrane was fabricated using phase inversion technique. CGW was taken from industry, weighed and manually cleaned. It was then subjected to alkali treatment for 2 hours with 10% Sodium Hydroxide (NaOH) at 80⁰C. The CGW was bleached with 5% Hydrogen Peroxide (H2O2). The CGW was then treated with 10% Sulfuric acid for 1 hour at 80⁰C. After filtering, the CGW fibers were oven dried for 3 hours. As a result of which, fine cellulose powder was obtained. For the fabrication of porous membrane, 3g of Polyvinyl Alcohol (PVA) was dissolved in 30 mL of distilled water. Another solution was prepared by the dissolution of 6g of Sodium Hydroxide (NaOH) and 6g of urea in distilled water and 1g of cellulose. The two solutions were mixed in a reflux assembly for 24 hours. This resulted in the fabrication of a cross-linked cellulose/polyvinyl alcohol (PVA) porous membrane. The fabricated membrane was used for the removal of heavy metals like copper, zinc and manganese from synthetic wastewater. The membrane was characterized by FTIR to identify the functional groups present in the membrane matrix and SEM analysis to find the pore size and morphology of the membrane. The maximum removal ofcopper was found to be 95% at 5 mg/L, 59.8% at 5 mg/L for zinc and 49.84% at 6mg/L concentration for manganese. This specified that the developed membrane could be effectively utilized for the removal of above mentioned heavy metals from wastewater.