Preparation and Characterization of Activated Carbon from Post-consumer Polyethylene terephthalate Bottles and its Applications in Carbofuran Detection and Removal

Abstract

Use of pesticides has utterly changed our society and has probably helped save millions from starvation, but it also present a threat to the environment as it easily contaminates surface and ground water. Carbofuran is one of the most widely used pesticide in India that is found to contaminate the ground water heavily, which is a major source of drinking water. It is essential to detect and remove carbofuran from water source in order protect human health and environment. Among various techniques available, electrochemical and adsorption is the most preferred methods for the detection and removal of pollutants in the environment. Activated carbon (AC) is well known for its excellent electrical conductivity and high adsorbent capacity due to its high surface area and large pore volume. In recent years, enormous research has been focused towards converting the solid wastes into activated carbon, since this technology not only solves the problem of waste disposal but also converts a potential waste into a valuable product that can be used for different applications. Post-consumer polyethylene terephthalate (PET) bottles, a solid polymer waste was selected as the raw material for the preparation of activated carbon in the present research work. Activated carbon was prepared through chemical activation using potassium hydroxide (KOH-AC), sulfuric acid (H2SO4-AC) and zinc chloride (ZnCl2-AC). Influence of various process parameters such as impregnation ratio, activation temperature and holding time on yield and porous characteristics of prepared activated carbon were studied. Prepared activated carbons were characterized by N2 adsorption-desorption isotherms at 77 K to obtain surface area, pore volume and pore size distribution. The microcrystallinities of the activated carbons prepared were examined by X-ray Diffraction (XRD) analysis. Information on the surface functional groups were obtained by Fourier Transform Infrared (FT-IR) spectroscopy analysis. The microstructure of the ACs prepared were examined by Field-Emission Scanning electron microscopy (FESEM) and Transmission Electron Microscopy (TEM) analysis. The results showed that KOH-AC prepared at optimum conditions (5 impregnation ratio, 1000 ˚C carbonization temperature and 60 min holding time) exhibited maximum values for surface area (1808 m2 /g) and pore volume (1.38 cm3 /g) with maximum contributions from mesopore surface area (925 m2 /g) and mesopore volume (0.95 cm3 /g). KOH-AC prepared at optimum conditions were preferred among other ACs for electrochemical sensor and adsorption applications in the following studies....