Preparation, Physicochemical and Spectroscopic Characterization of Low-Cost Acid Functionalised Rice Husk Activated Carbon (AF-RHAC)

Abstract

The estimated 500 million tons of rice husk produced yearly around the world are frequently burned or carelessly dumped into bodies of water. However, rice husk can be transformed into inexpensively practical adsorbents with distinctive adsorption properties for the absorption of various pollutants. To achieve this, conversion of rice husk into activated carbon is required to increase its adsorption capacity. This paper reports the preparation, physicochemical and spectroscopic characterization of acid functionalized rice husk (AF -RHAC). AF-RHAC was successfully prepared by carbonization and chemical activation using 1 M orthophosphoric acid (H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> PO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> ) for 1 hr at 400 °C. The adsorbent was characterized by series of physicochemical techniques such as ash and moisture content, volatile matter, Boehm titration, surface area determination using sears method, Iodine number, Scanning Electron Microscopy (SEM) to ascertain the surface morphology, the surface functional group determined via Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD) analysis was applied to ascertain the adsorbents elemental composition. The physicochemical parameters showed pH values of (6.83), pH <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pzc</inf> (6.21), bulk density (0.48), moisture content (8.45 %), ash content (18.45 %), volatile matter (32.31 %) and iodine number (553.72). The SEM images showed the existence and availability of pores on the adsorbents surface which acts as adsorption sites. FTIR revealed presence of functional groups for effective adsorption and XRD results revealed the materials structure of AF-RHAC.