Functionalization of Wood Char for Adsorption of Organic Contaminant

Abstract

Wood char is a carboneous pyrolized product which can used as both adsorbent and catalyst matrix. Quality of the wood char can be improved by activation, oxidation, and modification using oxide metals. Those treatment can increase its porosity, acid functional groups, and Lewis site, respectively, which increase its affinity toward organic substance. Purpose of this research is to study influence of functionalization of woodchar toward chemical property of thechar/carbon and adsorption of paracetamol. The activation of wood char was conducted by using KOH activator at 500 oC, the oxidation was performed using concentrate HNO3 solution at 80 oC, and modification by using Zn-Fe-LDH (Layered Double Hydroxide) and ZnFe2O4. Mol ratio of Fe(III)/Zn(II) was adjusted at 5:1. Adsorption test was performed by batch method (50 ppm of paracetamol; 0.1 g of adsorbent; at 200 rpm for 24h). Adsorption capacity was determined at the same condition, except at various concentration of paracetamol (10-100 ppm). Characterization using FTIR spectrophotometry confirms that functionalization gave peak changes of M-O, M-OH,-OH, C-O, and C=C. XRD characterization indicates the ZnFe2O4 structure for the calcined Zn-Fe-LDH. EDS confirms content of Fe (29.5 %w), Zn (7.7%w), O (18.2%w). SEM characterization indicated that ZnFe2O4/AC composite has irregular shape particle with some holes on its surface. Adsorption test confirms that ZnFe2O4/AC composite gave adsorption percentage of paracetamol about 4 times larger than wood char, 2.8 times larger than activated carbon, and 1.5 times larger than Zn-Fe-LDH/AC composite. Adsorption capacity of paracetamol by ZnFe2O4/AC is 7.36 mg/g (Langmuir model) and 5.63 mg/g (Dubinin Radushkevic model). Adsorption energy is 223.61 J/mol, indicating the physical adsorption mechanism.