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Recovery of Zn2+ and Ni2+ binary from wastewater using integrated biosorption and electro-deposition

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thesis
posted on 23.05.2021, 18:19 by Shahrad K. Booran
In 2012, the United States environmental protection agency (USEPA) prepared a list of 129 organic and inorganic pollutants found in wastewater that constitute serious health hazards. This list includes the following heavy metals: cadmium, chromium, lead, mercury, nickel and zinc. The effects of bed depths from 0.5 to 2.0 m, liquid flow rates from 0.1 to 0.5 L.min-1, biosorbent particle sizes of 0.5 to 2 inches (1.27 - 5.08 cm) and metal concentrations from 10 to 50 mg-Zn-Ni/L on biosorption service were investigated. The best performance in biosorption of ZN2+ and Ni2+ binary solutions was at the smallest biosorbent particle size (0.5 inch), highest bed depth (2 m), lowest flow rate (0.1 L.min-1) and smallest initial concentration (10 mg/L). For biomass regeneration, the effects of the type of desorbing agents (hydrochloric acid, nitric acid and sulphuric acid), concentrations (0.1 to 0.5 M) and flow rates (0.05 to 0.1 L/min) on recovery of Zn2+ and Ni2+ binary mixture were investigated. The best performance in desorption of Zn2+ and Ni2+ binary solutions were 0.1 M H2S04 and a 0.05 L/min inlet flow rate. Moreover, the reusability of wheat straw was examined by carrying out five successive biosorption/desorption, and the results indicated that wheat straw retained its zinc and nickel adsorption capacity in all five sorption/desorption cycles. Electro-deposition was also used to remove metal ions from concentrated ZN+2 and Ni+2 binary solutions (about 340 ppm) from the desorption step. It was found that the electro-deposition could reduce the metal concentrations down to wastewater discharge limit of 2 mg-Zn-Ni/L. Lastly, economical evaluation showed that the recovery of the heavy metals using Integrated Biosorption and Electro-deposition has great advantages from both technical and economical perspectives over the chemical precipitation technology.

History

Degree

Master of Engineering

Program

Chemical Engineering

Granting Institution

Ryerson University

LAC Thesis Type

Thesis