Application of low-cost adsorbents for dye removal – A review

https://cyberleninka.org/article/n/999493.pdf

New trends in removing heavy metals from industrial wastewater

Biosorbents for heavy metals removal and their future

A review on the utilization of fly ash

Microbial and plant derived biomass for removal of heavy metals from wastewater.

In this paper, tea leaves were shown to be an effective, low-cost biosorbent. Removal of lead, iron, zinc and nickel from 20 mg/L metal solution by dried biomass of waste tea leaves amounted to 96, 91, 72 and 58 %, respectively, at equilibrium, which followed Langmuir and Freundlich adsorption isotherms. Adsorption of metal was in the order of Pb > Fe > Zn > Ni from 5-100 mg/L of metal solution. From a multi-metallic mixture, 92.5, 84 and 73.2 % of lead, iron and zinc, respectively, were removed. Fourier transform infrared (FTIR) studies indicated that the carboxyl group was involved in the binding of lead and iron, whereas the amine group was involved in the binding of nickel and zinc. A flow through sorption column packed with dried biomass demonstrated a sorption capacity of 73 mg Pb/g of biomass, indicating its potential in cleaning metal containing wastewater. The metal laden biomass obtained could be disposed off by incineration.

Removal of Heavy Metals by Waste Tea Leaves from Aqueous Solution

Removal of heavy metals (Pb2+, Zn2+) from aqueous solution by dried biomass of Spirulina sp. was investigated. Spirulina rapidly adsorbed appreciable amount of lead and zinc from the aqueous solutions within 15 min of initial contact with the metal solution and exhibited high sequestration of lead and zinc at low equilibrium concentrations. The specific adsorption of both Pb2+ and Zn2+ increased at low concentration and decreased when biomass concentration exceeded 0.1 g l−1. The binding of lead followed Freundlich model of kinetics where as zinc supported Langmuir isotherm for adsorption with their r
 2
 values of 0.9659 and 0.8723 respectively. The adsorption was strongly pH dependent as the maximum lead biosorption occurred at pH 4 and 10 whereas Zn2+ adsorption was at pH 8 and 10.

/pdf/biosorption-of-pb2-and-zn2-by-non-living-biomass-of-124lnsbq04.pdf

Biosorption of Pb2+ and Zn2+ by Non-Living Biomass of Spirulina sp.

Chromium compounds are released by industrial processes including leather production, mining, petroleum refining, in textile industry and dyeing. They are a significant threat to the environment and public health because of their toxicity. Removal of hexavalent chromium by living biomass of different fungi was effective in the order of Aspergillus terricola>Aspergillus niger>Acremonium strictum>Aureobasidium pullulans>Paecilomyces variotii>Aspergillus foetidus>Cladosporium resinae>Phanerochaete chrysosporium. Non-living dried fungal biomass showed higher potential for metal removal than living cells. Among all fungi dead biomass of P. chrysosporium, C. resinae and P. variotii had the maximum specific chromium uptake capacity, which was 11.02, 10.69 and 10.35 mg/g of dry biomass respectively at pH 4.0–5.0 in batch sorption. Removal of Cr(VI) by P. chrysosporium from multi-metallic synthetic solution as well as chrome effluent was significant by bringing down the residual concentration to 0.1 mg/L in the effluent, which falls within the permissible range and its removal was not affected by the presence of other metal ions such as Fe, Zn and Ni. Fourier transform infrared spectral analysis revealed the presence of carboxylate (C=O) and amine (−NH, −NH) functional groups commonly present on the cell surface of all fungi, with possible involvement in chromium binding. The result indicates that non-living fungal biomass either obtained as a by-product of fermentation industry or mass produced using inexpensive culture media can be used for bioremediation of Cr(VI) from chrome effluent on large scale.

Sarabjeet Singh Ahluwalia

Papers

Microbial and plant derived biomass for removal of heavy metals from wastewater.

Removal of Heavy Metals by Waste Tea Leaves from Aqueous Solution

Biosorption of Pb2+ and Zn2+ by Non-Living Biomass of Spirulina sp.

Removal of Cr(VI) from aqueous solution by fungal biomass

Advances in Environmental Biotechnology