Recycling PVC Waste into Functional Adsorbent for Dye Removal: An Eco-Friendly Approach

Abstract

Environmental pollution caused by improper emissions of toxic dyes from industries has become major concern nowadays in developing countries. A facile route has been explored to develop new cost-effective modified waste material-based adsorbent. Plastic solid wastes such as waste PVC pipes were processed and converted into functional material which was applied in dye removal technology. PVC was separated from plastic wastes with extraction yield of 78%. Isolated PVC was modified functionally by treating with ethylenediamine. Characterization of product by elemental analysis, XPS, and FT-IR techniques confirmed the formation of aminated PVC (APVC). A series of adsorption batch experiments were carried out by APVC to remove methylene blue (MB) dye from solutions. MB removal efficiency was optimized by varying different experimental parameters including solution pH, contact time, dye concentration, adsorbent dose, and temperature. An adsorption capacity of 10.45 mg/g with 52.25% of MB removal was recorded at optimized conditions (pH 10, contact time 11 hours, dye concentration of 20 ppm, adsorbent dose of 10mg/10mL, and temperature of 30°C). Experimental data were best suited to Langmuir isotherm (R2 = 0.9699) and followed Pseudo 2nd order kinetics (R2 = 0.9914). Evaluation of different thermodynamic parameters (Negative ΔG°, ΔH° = 9.7524 KJ mole-1, ΔS° = 33.5474 J K-1 mole-1) demonstrated spontaneous and endothermic nature of MB adsorption process on APVC. These results revealed new avenue of plastic solid wastes management by recycling and modification of PVC wastes into valuable functional material which worked as potential adsorbent for efficient removal of dyes from wastewater system.