Experiments have been carried out to characterize the adsorption of chromium(VI) in the aqueous phase onto dried roots of water hyacinth. Results revealed a very high degree of removal efficiency (~100%). Theoretical analyzes are also made for describing the sorption and diffusion processes. The effective pore diffusivity of chromium(VI) in the water hyacinth roots is determined by a suitable global optimization technique. The depth of penetration, on the other hand, has been estimated for various initial concentrations of chromium(VI). Theoretically predicted concentration profiles are in excellent agreement with the experimental values. © 2010 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

DEBASISH SARKAR

Chemical Engineering

SUDIP DAS

DEBASIS SARKAR

Applied Mathematics

AMITAVA BANDYOPADHYAY

P MUKHERJEE

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Clean - Soil, Air, Water

Proposed adsorption-diffusion model for characterizing chromium(VI) removal using dried water hyacinth roots

In this paper, we have presented the results of Cr(VI) and Cr(III) removal from aqueous phase by different aquatic weeds as biosorbents. Batch kinetic and equilibrium experiments were conducted to determine the adsorption kinetic rate constants and maximum adsorption capacities of selected biosorbents. In most of the cases, adsorption followed a second-order kinetics. For Cr(III), maximum adsorption capacity was exhibited by reed mat (7.18 mg/g). In case of Cr(VI), mangrove leaves showed maximum removal/reduction capacity (8.87 mg/g) followed by water lily (8.44 mg/g). There was a significant difference in the concentrations of Cr(VI) and total chromium removed by the biosorbents. In case of Cr(VI) removal, first it was reduced to Cr(III) with the help of tannin, phenolic compounds and other functional groups on the biosorbent and subsequently adsorbed. Acid treatment significantly increased Cr(VI) removal capacity of the biosorbents whereas, alkali treatment reduced the Cr(VI) removal capacities of the biosorbents. FTIR spectrum showed the changes in functional groups during acid treatment and biosorption of Cr(VI) and Cr(III). Aquatic weeds seem to be a promising biosorbent for the removal of chromium ions from water environment. © 2007 Elsevier B.V. All rights reserved.

Journal of Hazardous Materials

Biosorption of chromium species by aquatic weeds: Kinetics and mechanism studies

In this paper, results of Cr(VI) and Cr(III) sorption from aqueous phase by palm flower (Borassus aethiopum) is presented. Batch kinetic and equilibrium experiments were conducted to determine the adsorption kinetic rate constants and maximum adsorption capacities. Both Cr(III) and Cr(VI) adsorption followed a second-order kinetics. For Cr(III), maximum adsorption capacity was 6.24 mg/g by raw adsorbent and 1.41 mg/g by acid treated adsorbent. In case of Cr(VI), raw adsorbent exhibited a maximum adsorption capacity of 4.9 mg/g, whereas the maximum adsorption capacity for acid treated adsorbent was 7.13 mg/g. There was a significant difference in the concentrations of Cr(VI) and total chromium removed by palm flower. In case of Cr(VI) adsorption, first it was reduced to Cr(III) with the help of tannin and phenolic compounds and subsequently adsorbed by the biosorbent. Acid treatment significantly increased Cr(VI) adsorption capacity of the biosorbent whereas, alkali treatment reduced the adsorption capacities for Cr(VI). However, in case of Cr(III), acid treatment significantly reduced the adsorption capacity whereas the adsorption capacity of alkali treated biosorbent was slightly less than that of raw adsorbent. FT-IR spectrum showed the changes in functional groups during acid treatment and biosorption of Cr(VI) and Cr(III). Column studies were conducted for Cr(III) to obtain the design parameters require for scale-up. © 2007 Elsevier B.V. All rights reserved.

Chemical Engineering Journal

Biosorption of hexavalent and trivalent chromium by palm flower (Borassus aethiopum)

Chromium removal from electroplating wastewater by coir pith

The effectiveness of low cost agro-based materials namely, Tamarindus indica seed (TS), crushed coconut shell (CS), almond shell (AS), ground nut shell (GS) and walnut shell (WS) were evaluated for Cr(VI) removal. Batch test indicated that hexavalent chromium sorption capacity (qe) followed the sequence qe(TS) ≥ qe(WS) ≥ qe(AS) ≥ qe(GS) ≥ qe(CS). Due to high sorptive capacity, tamarind seed was selected for detailed sorption studies. Sorption kinetic data followed first order reversible kinetic fit model for all the sorbents. The equilibrium conditions were achieved within 150 min under the mixing conditions employed. Sorption equilibria exhibited better fit to Freundlich isotherms (R ≥ 0.92) than Langmuir isotherm (R ≈ 0.87). Hexavalent chromium sorption by TS decreased with increase in pH, and slightly reduced with increase in ionic strength. Cr(VI) removal by TS seems to be mainly by chemisorption. Desorption of Cr(VI) from Cr(VI) laden TS was quite less by distilled water and HCl. Whereas with NaOH, maximum desorption achieved was about 15.3%. When TS was used in downflow column mode, Cr(VI) removal was quite good but head loss increased as the run progressed and was stopped after 200 h. © 2005 Elsevier Ltd. All rights reserved.

Journal	Data powered by TypesetClean - Soil, Air, Water
Publisher	Data powered by TypesetWILEY-BLACKWELL
ISSN	1863-0650
Open Access	No