Utility
of adsorbents in the purification of drinking water: A review of
characterization, efficiency and safety evaluation of various adsorbents
Shashi Prabha Dubey1, Krishna Gopal*1 and
J.L. Bersillon2
1Aquatic
Toxicology Division, Industrial Toxicology Research Centre, P.B. No. 80,
M.G.
Marg, Lucknow
- 226 001, India
2Laboratoire Environment et Mineralurgie, Groupe de Recheerches sur I’Eau et les Solides Divises,
Centre
de Recheche Francois Fiessinger,
Nancy - F-54501, Cedex,
France
(Received:
June 21, 2007; Revised received: December 04, 2007; Accepted: January 02, 2008)
Abstract: Clean drinking water is one of the implicit requisites for a healthy
human population. However, the growing industrialization and extensive use of
chemicals for various concerns, has increased the burden of unwanted pollutants
in the drinking water of developing countries like India. The entry of potentially
hazardous substances into the biota has been magnifying day by day. In the
absence of a possible stoppage of these, otherwise, useful chemicals, the only
way to maintain safer water bodies is to develop efficient purifying
technologies. One such immensely beneficial procedure that has been in use is
that of purification of water using ‘adsorbents’. Indigenous minerals and
natural plants products have potential for removing many pollutants viz.
fluoride, arsenic, nitrate, heavy metals, pesticides as well as trihalomethanes. Adsorbents which are derived from carbon,
alumina, zeolite, clay minerals, iron ores,
industrial by products, and natural products viz. parts of the plants, herbs
and algal biomass offer promising potential of removal. In the recent years
attention has been paid to develop process involving screening / pretreatment /
activation / impregnation using alkalies, acids,
alum, lime, manganese dioxide, ferric chloride and other chemicals which are
found to enhance their adsorbing efficiency.
Chemical characterization of these adsorbents recapitulates the
mechanism of the process. It is imperative to observe that capacities of the
adsorbents may vary depending on the characteristics, chemical modifications
and concentration of the individual adsorbent. Removal kinetics is found to be
based on the experimental conditions viz. pH, concentration of the adsorbate, quantity of the adsorbent and temperature. It is
suggested that isotherm model is suitable tool to assess the adsorption
capacities in batch and column modes. Safety evaluation and risk assessment of
the process/products may be useful to provide guidelines for its sustainable
disposal.
Key words: Efficiency, Characterization, Langmuir,
Freundlich, BET
PDF of full length paper is
available with author (* krishnagopaldubey@gmail.com)
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