@article { ISI:000257637000008, title = {Adsorption of fluoride ions by Zn-Al layered double hydroxides}, journal = {Applied Clay Science}, volume = {40}, number = {1-4}, year = {2008}, month = {JUN}, pages = {54-62}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Zn-Al layered double hydroxides (LDHs) with different molar ratios Zn/Al (0, 0.17, 0.34, 0.97, 3.47, proportional to) were prepared by the co-precipitation of chlorides, characterized and evaluated for their fluoride adsorption at room temperature from aqueous solutions. The fluoride adsorption of the as-synthesized LDHs was influenced by the chemical composition of the LDHs and ZA-11 (Zn/Al = 0.97) had the highest capacity for fluoride adsorption (1.14-4.16 mg/g). The adsorption increased after calcination of the LDH up to 500 degrees C. The equilibrium data were fitted to the Freundlich, Langmuir, and Temkin equations. The kinetics of fluoride adsorption followed the pseudo-second order model. (C) 2007 Elsevier B.V All rights reserved.

}, keywords = {Adsorption, Anionic clay, Fluoride, Layered double hydroxide}, issn = {0169-1317}, doi = {10.1016/j.clay.2007.07.004}, author = {Mandal, Sujata and Mayadevi, S.} } @article { ISI:000257474100021, title = {Cellulose supported layered double hydroxides for the adsorption of fluoride from aqueous solution}, journal = {Chemosphere}, volume = {72}, number = {6}, year = {2008}, month = {JUN}, pages = {995-998}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Cellulose supported layered double hydroxides (CSLDHs) were synthesized and tested for adsorption of fluoride in aqueous medium. Three samples of cellulose supported LDHs were synthesized by varying the LDH loading on cellulose. The raw cellulose, unsupported LDH and cellulose supported LDHs were characterized by XRD, SEM and BET surface area. Batch adsorption as well as fixed-bed column experiments were performed for determining the fluoride adsorption characteristics of CSLDHs. The fluoride adsorption properties of CSLDHs were found to be superior to that of reported adsorbents, including activated alumina and carbon nanotubes. Defluoridation capacity of the CSLDHs was 2-4 times higher than that of unsupported LDH. The cellulose supported LDH, CSLDH-50, having an LDH loading of 27\% showed maximum fluoride uptake capacity (5.29 mg g(-1) of CSLDH, 25.18 mg g(-1) of LDH) in fixed-bed column study. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Adsorption, cellulose, Fluoride, Layered double hydroxide}, issn = {0045-6535}, doi = {10.1016/j.chemosphere.2008.03.053}, author = {Mandal, Sujata and Mayadevi, S.} } @article {49063, title = {Synthetic layered double hydroxide on biodegradable support: an efficient adsorbent for defluoridation of water}, journal = {Indian Journal of Chemical Technology }, volume = {31}, year = {2024}, month = {JAN}, pages = {152-161}, type = {Article}, abstract = {

Fluoride concentrations in drinking water above permissible levels and incidences of fluorosis among people have been reported from many parts of the world including India. Low-cost and biodegradable adsorbents are the preferred choice for the removal of fluoride from an aqueous medium. In the present study, zinc-aluminium layered double hydroxide (LDH) supported on sugarcane bagasse (raw and acid-treated) has been synthesized, characterized, and investigated for the defluoridation of water. The SEM micrographs of the supported adsorbents show good dispersion of the LDH particles on the support material. The defluoridation capacity of the LDH is enhanced by supporting it on bagasse. The adsorption capacity of supported adsorbents increased by 3-fold than the unsupported LDH adsorbent. The adsorption data have been well fitted to the Freundlich isotherm model indicating physical and multi-layer adsorption. The maximum fluoride adsorption capacity has been found to be 8.85 mg/g with 76.3\% fluoride removal when the initial fluoride concentration is 11-12 mg/L. The pseudo-second-order kinetic model has been found suitable to explain the fluoride adsorption kinetics on the supported LDH adsorbents. The present study reveals that the bagasse-supported LDH adsorbent has a high potential for defluoridation of water.

}, keywords = {adsorption kinetics, Fluoride adsorption, Layered double hydroxide, Sugarcane bagasse}, issn = {0971-457X}, doi = {10.56042/ijct.v31i1.7611}, author = {Mayadevi, S. and Kirandas, M. D. and Manilal, A. M. and Roshini, N. and Mandal, Sujata} }