Bioremediation of toxic metals and recovery of target metals from actual wastewater using Algal sorbents
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Date
Authors
Birungi, Z.S. (Zainab)
Chirwa, Evans M.N.
Journal Title
Journal ISSN
Volume Title
Publisher
The Italian Association of Chemical Engineering
Abstract
The use of biological material is an emerging and environmentally friendly technology with great prospects to
effectively clean up toxic metals at low concentrations and possible recovery for re-use in industry. The living
biomass accumulates high levels of metals but possible recovery without cell disruption seems almost
impossible. Biosorption is a term often used to refer to the treatment of wastewater containing heavy metals
using dead biomass. This study utilised algal samples collected from a eutrophic dam and isolated pure
strains for use in biosorption experiments. Two species Chlorella vulgaris and Chlamydomonas reinhardtii
were identified and tested for their ability to remove and or reduce the concentration of metals in simulated
and industrial wastewater. The algal species were initially tested for their biosorption potential for
removal/recovery of Lanthanum (La) and Thallium (Tl) in single metallic studies. In addition, test algae was
characterised before and after adsorption using Surface Electron Microscope (SEM). Chlamydomonas
reinhardtii showed the highest sorption capacity (qmax) of 143 mg/g compared to Chlorella vulgaris with a qmax
of 75 mg/g for removal of La. Both species showed a similar qmax for removal of Tl at 1000mg/g but
Chlamydomonas reinhardtii had a higher affinity (b) of 1.67 L/g. Wastewater from the mine beneficiary plant
showed complete removal of Cobalt from an initial concentration of 0.316 mg/L by C. vulgaris. Industrial
water from smelter clave tailings showed Tl as the highest heavy metal concentration of 2.386 mg/L which
was reduced to 0.021 mg/L using C. vulgaris. Potassium was reduced significantly by C.reinhardtii from 2036
to 744.7 mg/L. Smelter return water had the highest level of Cr at 135.56 mg/L and was reduced to 45.67mg/L
by C.vulgaris. The tested algal sorbents showed potential for the treatment of actual wastewater with the best
adsorbent performance from C. vulgaris.
Description
Keywords
Chemicals removal (water treatment), Low concentrations, Initial concentration, Industrial wastewater, Heavy metal concentration, Environmentally-friendly technology, Chlorella vulgaris, Chlamydomonas reinhardtii, Wastewater treatment, Smelting, Molecular biology, Metal recovery, Heavy metals, Biosorption, Bioremediation, Biological materials
Sustainable Development Goals
Citation
Birungi Z., Chirwa E., 2018, Bioremediation of toxic metals and recovery of target metals from actual wastewater using algal sorbents, Chemical Engineering Transactions, 64, 535-540 DOI: 10.3303/CET1864090.