Chromium adsorption on surface activated biochar made from tannery liming sludge: A waste-to-wealth approach

Authors: HASHEM, MD - Khulna University Of Engineering & Technology (KUET); PAYEL, SOFIA - Khulna University Of Engineering & Technology (KUET); MIM, SADIA - Khulna University Of Engineering & Technology (KUET); HASAN, MD - Khulna University Of Engineering & Technology (KUET); NUR-A-TOMAL, MD - Khulna University Of Engineering & Technology (KUET); RAHMAN, MD - Department Of Public Health Engineering (DPHE); Sarker, Majher

Submitted to: Water Science and Engineering Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2022
Publication Date: 9/6/2022
Citation: Hashem, M.A., Payel, S., Mim, S., Hasan, M.A., Nur-A-Tomal, M.S., Rahman, M.A., Sarker, M.I. 2022. Chromium adsorption on surface activated biochar made from tannery liming sludge: A waste-to-wealth approach. Water Science and Engineering Journal. 15(4):328-336. https://doi.org/10.1016/j.wse.2022.09.001.
DOI: https://doi.org/10.1016/j.wse.2022.09.001

Interpretive Summary: In leather processing, liming is an important step to remove hair/wool and epidermis from animal hide/skins. But it creates problems by discharging waste liming sludge to the environment. The treatment of tannery wastewater is also another big challenge for the industry. In this study, thermally activated biochars produced from solid liming sludge are studied for their effective adsorption of chromium (Cr) (a heavy metal used in leather tanning) from the tannery wastewater. The thermally activated biochars are prepared from the liming sludge by heating them at 500 degree C, 550 degree C, 600 degree C, and 650 degree C and are characterized using different laboratory equipment. Biochar originating from the tannery liming sludge at 600°C is found to be the best with 99.8% chromium adsorption capacity from leather tannery wastewater. The study indicates an innovative pathway of utilizing liming sludge waste to minimize the pollution load and cost of wastewater treatment of tannery industries.

Technical Abstract: In a beamhouse leather tannery, liming plays a key role in the removal of hair/wool and epidermis, but it also creates problems by discharging waste liming sludge to the environment. The treatment of tannery wastewater is another big challenge for the industry. In this paper, thermally activated biochars derived from liming sludge are studied for their effective adsorption of chromium (Cr) from the tannery wastewater. The thermally activated biochars are prepared from the liming sludge at 500 degree C, 550 degree C, 600 degree C, and 650 degree C and characterized using FT-IR, EDX, Brunauer-Emmett-Teller (BET) and SEM analysis before and after use. These analyses determine the related functional groups (C-H, O-H, C-N, =C-O), chromium adsorption capacity through the surface morphology, element contents (C, O, Ca, Na, Al, Mg, Si), surface area (5.8-9.2 m2/g), pore size (5.22-5.53 nm), and particle size (652-1034 nm) of the experimental biochars. Biochar originating from the tannery liming sludge at 600 degree C is found in higher surface area with 99.8% chromium adsorption capacity when compared with the other thermally activated biochars at 500 degree C, 550 degree C and 650 degree C. The study indicates an innovative pathway of utilizing liming sludge waste to minimize the pollution load and cost of waste-water treatment of tannery industries.