Abstract
In this paper, carbonaceous hydrochar adsorbents with highly functionalized surface active sites were prepared from cellulose and lignin constitutes of rice straw via hydrothermal treatment at 180oC for 20h followed by carbonization process at 500oC for 2h without external gas flow. Two carbonaceous samples were obtained from cellulose and lignin and denoted as RC-C and RL-C, respectively. The resulting hydrochar adsorbents were characterized using means of SEM, TEM, FTIR, Boehm's titration and adsorption of N2 gas at -196oC. Kinetic and equilibrium adsorption studies using methylene blue (MB) dye as model pollutant compound in industrial wastewaters were determined. The calculated adsorption efficiencies of the adsorbents were considerably depended on the initial dye concentration, contact time and temperature. The obtained adsorption results were found to describe well using the pseudo-second order kinetic and Langmuir isotherm models. Monolayer adsorption capacity of RC-C and RL-C reached to 100 and 40 mg/g towards MB dye, respectively. Based on these findings, the produced hydrochars from cellulose and lignin of rice straw can be emerged as low-cost and valuable adsorbents for removing dye contaminants from wastewater.