Cr(VI) removal by a new biocarbon material prepared from local S. Thaipingensis ('Pokok Gapis') leaf biomass: Characterization, isotherm and kinetic studies

• Main Authors: Palsan Sannasi, Abdullah, Foong, Jenny Chau Hui*, Nuramira Najua, Md Hafiz
• Format: Article
• Language: English
• Published: Medwell Publishing 2017
• Subjects: TP Chemical technology
• Online Access: http://eprints.intimal.edu.my/964/1/Cr%28VI%29%20removal%20by%20a%20new%20biocarbon%20material%20prepared%20from%20local%20S.%20Thaipingensis.pdf; http://eprints.intimal.edu.my/964/

This study reports the preparation of a new biocarbon material from the leaf biomass of local S. thaipingensis tree by heat treatment for use as low cost bioadsorbent material for Cr(VI) removal. To the best of our knowledge there is no literature to date on the exploitation of this species for similar purpose. The newly prepared biocarbon had higher carbon (58.35%) and lower ash (5.98%) content than its precursor. Batch sorption experiment was carried out at varying contact time (30-300 min), biocarbon dosage (0.125-0.500 g), initial pH(2-8) and Cr(VI) concentrations (10-100 mg/L) to ascertain Cr(VI) removal capability. Results showed that 0.125 g of biocarbon material was able to remove Cr(VI) as much as 72.72±0.27 to 98.81±0.82% at 10-100 mg/L, pH 2 and 180 min of agitation time (p<0.05). Adsorption followed the Freundlich model (Kf = 4.80, n = 2.85, R2 = 0.9963) and pseudo-second order kinetics (R2 = 0.9946) implying a multilayer surface chemisorption accompanied by interactions between the adsorbed Cr on the biocarbon surface and Cr ions in the solution. SEM examination revealed pore like structures that can adsorb Cr in the biocarbon and the rich and diverse chemical functional groups (-C-H-, -C-C-, -C = C-, -C-N-, -N-H-) and oxides (Ca, Na, Si) that can facilitate adsorption were observed through FTIR and XRF analyses. This study affirms the suitability of S. thaipingensis leaf powder biomass as a biocarbon precursor for use as low cost bioadsorbent material for waste effluent remediation.