Packed bed column studies on Cr (VI) removal from tannery wastewater by neem sawdust

• Published in: Desalination 2010-12, Vol.264 (1), p.9-14
• Main Authors: Vinodhini, V., Das, Nilanjana
• Format: Article
• Language: English
• Subjects: Adsorption; Applied sciences; Biological and medical sciences; Biosorption; Biotechnology; Chemical engineering; Chromium; Chromium (VI); Column packings; Effluents; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General purification processes; Methods. Procedures. Technologies; Neem sawdust; Others; Packed bed column; Pollution; Sawdust; Surface chemistry; Tanneries; Tannery wastewater; Various methods and equipments; Waste water; Wastewaters; Water treatment and pollution
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2010.06.073

The removal of Cr (VI) from tannery wastewater by neem sawdust was investigated in a fixed bed column. The experiments were conducted to study the effect of important parameters such as bed depth (5–15 cm) and flow rate (5–15 ml min − 1 ). The bed depth service time model (BDST) fit well with the experimental data. The adsorption capacity estimated from the BDST model was 33,009.9 mg g − 1 . The column was regenerated by eluting chromium (VI) using 2 N NaOH after adsorption studies. The desorption of Cr (VI) failed to reach 100% in each cycle because some amount of adsorbed Cr (VI) got reduced to Cr (III) in the biosorbent surface and released into the aqueous phase. The effect of co-ions on adsorption of Cr (VI) was studied in column mode, where the breakthrough and the exhaustion time of the column decreased in the presence of co-ions. In the three cycles of biosorption, about 3.75 L of tannery effluent were treated to reach the chromium (VI) standard (0.1 mg L -1) established by the Central Pollution Control Board (CPCB). Neem sawdust proved to be the potential biosorbent for the removal of Cr (VI) from tannery effluents.