01451nas a2200205 4500008004100000022001400041245006700055210006600122260007300188300001000261490000700271520075900278653001501037653001701052653001301069653002901082100001901111700001701130856009801147 2008 eng d a0169-131700aAdsorption of fluoride ions by Zn-Al layered double hydroxides0 aAdsorption of fluoride ions by ZnAl layered double hydroxides aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUN a54-620 v403 a

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.

10aAdsorption10aAnionic clay10aFluoride10aLayered double hydroxide1 aMandal, Sujata1 aMayadevi, S. uhttps://library.ncl.res.in/content/adsorption-fluoride-ions-zn-al-layered-double-hydroxides-001754nas a2200205 4500008004100000022001400041245010300055210006900158260010600227300001200333490000700345520096500352653001501317653001401332653001301346653002901359100001901388700001701407856012401424 2008 eng d a0045-653500aCellulose supported layered double hydroxides for the adsorption of fluoride from aqueous solution0 aCellulose supported layered double hydroxides for the adsorption aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUN a995-9980 v723 a

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.

10aAdsorption10acellulose10aFluoride10aLayered double hydroxide1 aMandal, Sujata1 aMayadevi, S. uhttps://library.ncl.res.in/content/cellulose-supported-layered-double-hydroxides-adsorption-fluoride-aqueous-solution-002178nas a2200241 4500008004100000022001400041245011600055210006900171260000800240300001200248490000700260520134600267653002401613653002401637653002901661653002201690100001701712700002101729700002001750700001601770700001901786856013101805 2024 eng d a0971-457X00aSynthetic layered double hydroxide on biodegradable support: an efficient adsorbent for defluoridation of water0 aSynthetic layered double hydroxide on biodegradable support an e cJAN a152-1610 v313 a

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.

10aadsorption kinetics10aFluoride adsorption10aLayered double hydroxide10aSugarcane bagasse1 aMayadevi, S.1 aKirandas, M., D.1 aManilal, A., M.1 aRoshini, N.1 aMandal, Sujata uhttps://library.ncl.res.in/content/synthetic-layered-double-hydroxide-biodegradable-support-efficient-adsorbent-defluoridation