Physico-chemical Characterization of a Biochar using a Fourier Transform Infra-Red Spectrophotometer and Physical Analysis: A Preliminary Study for Preparation of Heavy Metal Absorption Research
Djoko Mulyanto(a), Arif Umami(b), Miseri Roeslan Afani(a), Ali Munawar(a)

a). Department of Soil Science, UPN Veteran Yogyakarta, Indonesia
b). Department of Agrotechnology, UPN Veteran Yogyakarta, Indonesia

Abstract

Biochar is a stable carbon-rich material produced from biomass through a pyrolysis heating method. The high carbon content, large surface area of the particles, and functional groups and cavities in certain shapes make biochar potential for various purposes, especially the binding of heavy metals and other pollutants from various wastes. To optimally use biochar as an adsorbent, it is necessary to understand its physical and chemical characteristics. This study aimed to characterize the physico-chemical properties of a biochar obtained from a local agricultural field. The Biochar of rice straw, each at a heating temperature of 300, 500, and 700 oC, was ground through 5 mesh and analyzed using FTIR to determine its functional groups. Proximate analysis of each biochar includes the content (% by weight) of water, volatile substances, ash, and % by weight of carbon to determine the material^s efficiency at heating temperature. The results showed that the higher pyrolysis temperatures of 300, 500, and 700 0C successively showed increasing average moisture content of 1.9%, 2.4%, and 3.3%, decreasing volatile content of 27.5%, 18.5%, and 11.6%, increasing ash content of 44.3%, 50.5%, 54.85%, and rising fixed carbon content of 26%, 28.5%, and 30%. The chemical structure evolution of biochar during rapid pyrolysis was studied using the FTIR method. The signal strength of the peak for hydroxyl groups ( O - H ) weakened concerning the raised temperature, indicating a reduction in hydroxyl group content. Rising temperatures also caused the reduction of aliphatic hydrocarbon ( C - H ), carbonyl, and carboxyl (C - O) bonds, whereas aromatic hydrocarbon content demonstrated the development of aromatization.

Keywords: Adsorbent, biochar of rice straw, physico-chemical characterization

Topic: Agriculture