Inorganic/Analytical/environmental chemist. Taught inorganic chemistry for last 36 years under WBES and posted at Presidency College since end of 1994-2011. Retiring from my post I had taken classes upto June 2017 as UGC Emeritus.
Surface-altered hydrous iron(III) oxide incorporating cerium(IV) (CIHFO) was prepared and charact... more Surface-altered hydrous iron(III) oxide incorporating cerium(IV) (CIHFO) was prepared and characterised via modern analytical tools for applications in fluoride removal from groundwater. The material with a Fe : Ce ratio of 1.0 : 0.5 (mol : mol) calcined at 473 K shows 24.8 AE 0.5 mg F À g À1 adsorption capacity at pH 5.0–7.0 from a solution with a concentration of 15.0 mg L À1 ; the material was established to be microcrystalline ($5 nm) with a 140.711 m 2 g À1 surface area, irregular surface morphology and porous structure. The time-dependent fluoride adsorption capacities of CIHFO at 293, 303 and 313 K are well described by the pseudo-first order, pseudo-second order and Weber–Morris kinetic models, respectively. The adsorption reaction occurs via a film/boundary layer diffusion process. The very low Arrhenius activation energy (E a ¼ 0.026 kJ mol À1) indicates the high feasibility of fluoride adsorption over CIHFO. The equilibrium data fit better with the Freundlich and Redlich–Peterson (g < 1.0) isotherms than with the Langmuir isotherm, which suggests multilayer adsorption. The values of the Freundlich parameters, n ¼ 3.10, 4.47 and 7.57 and K F ¼ 8.58, 10.88 and 11.25 at 293, 303 and 313 K, respectively, indicate high affinity for fluoride. Thermodynamic analysis of the reaction equilibrium shows that the reaction is highly exothermic (DH 0 ¼ À25.924 and À36.279 kJ mol À1 for C i ¼ 25.0 and 35.0 mg L À1), whereas the negative DG 0 values indicate the spontaneous nature of the reaction. The fluoride adsorption over CIHFO occurs via ion-exchange that progresses to chemisorption. The presence of sulphate shows an adverse influence on fluoride adsorption by CIHFO, and the fluoride level of 2.4 g per L groundwater (9.05 mg F L À1) can be reduced below the permissible value.
Manganese oxide incorporated ferric oxide nanocomposite (MIFN), a novel adsorbent has been synthe... more Manganese oxide incorporated ferric oxide nanocomposite (MIFN), a novel adsorbent has been synthesized , characterized and explored for the removal of Cr(VI) from contaminated water. Surface elemental composition of semi-crystalline adsorbent was analyzed by SEM-EDX spectroscopy and was found to contain Fe (42.5%), Mn (8.1%) and O (49.4%), confirming Fe/Mn mole ratio of 5.0. BET surface area, particle diameter, pore size and total pore volume of the adsorbent were estimated as 186.28 m 2 g −1 , 5–7 nm, 81.2 A 0 and 0.31 cm 3 g −1 respectively. The adsorption of Cr(VI) was highly pH sensitive, and maximum adsorption was achieved within pH 2.0–3.0. Adsorption kinetics were described well by pseudo 2nd order model and were followed by both film diffusion as well as intra-particle pore diffusion mechanism. Langmuir isotherm was recognized to be the best fit model and maximum monolayer adsorption capacity was estimated as 47.84 mg g −1 for Cr(VI) at pH 3.0 at 303 K. Thermodynamic analysis revealed that the adsorption was highly favorable, spontaneous and endothermic in nature. Adsorption of Cr(VI) was strongly inhibited by phosphate and sulphate, whereas fluoride, carbonate, bicarbonate and silicate have no significant interference. Adsorption efficiency of the spent adsorbent (MIFN) could be rejuvenated around 78–80% by 1.0 M NaOH and subsequently be reused. The present study revealed that MIFN could be an efficient adsorbent for scavenging Cr(VI) from contaminated water because of its high adsorption capacity and reusability.
The synthetic bimetal iron(III)-titanium(IV) oxide (NHITO) used was characterized as hydrous and ... more The synthetic bimetal iron(III)-titanium(IV) oxide (NHITO) used was characterized as hydrous and nanostructured mixed oxide, respectively, by the Föurier transform infra red (FTIR), X-ray diffraction (XRD) pattern and the transmission electron microscopic (TEM) image analyses. Removal of As(III) and As(V) using the NHITO was studied at pH 7.0 (+/-0.1) with variation of contact time, solute concentration and temperature. The kinetic sorption data, in general, for As(III) described the pseudo-first order while that for As(V) described the pseudo-second order equation. The Langmuir isotherm described the equilibrium data (303 (+/-1.6)K) of fit was well with the Langmuir model. The Langmuir capacity (q(m), mg g(-1)) value of the material is 85.0 (+/-4.0) and 14.0 (+/-0.5), respectively, for the reduced and oxidized species. The sorption reactions on NHITO were found to be endothermic and spontaneous, and took place with increasing entropy. The energy (kJ mol(-1)) of sorption for As(III) and As(V) estimated, respectively, is 9.09 (+/-0.01) and 13.51 (+/-0.04). The sorption percentage reduction of As(V) was significant while that of As(III) was insignificant in presence of phosphate and sulfate. The fixed bed NHITO column (5.1 cm x 1.0 cm) sorption tests gave 3.0, 0.7 and 4.5L treated water (As content &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.01 mg L(-1)) from separate As(III) and As(V) spiked (0.35+/-0.02 mg L(-1)) natural water samples and from high arsenic (0.11+/-0.01 mg L(-1)) ground water, respectively when inflow rate was (0.06 L h(-1)).
International Journal of Green Nanotechnology, 2011
ABSTRACT Two different TiO2 particles with nanodimensions were prepared by sol-gel (TO-S) and low... more ABSTRACT Two different TiO2 particles with nanodimensions were prepared by sol-gel (TO-S) and low temperature chemical precipitation method (TO-P) from a TiCl4 precursor. As a result, the TO-S preparation was according to the “green chemistry” method because it did ...
... Natural Resource Accounting for Soils: Towards an Empirical Estimate of Costs of Soil Degrada... more ... Natural Resource Accounting for Soils: Towards an Empirical Estimate of Costs of Soil Degradation for India. KS Parikh and U. Ghosh. ... Check the EconPapers FAQ or send mail to . EconPapers is hosted by the Swedish Business School at Örebro University. ...
Fluoride is an accumulative poison at high dose of intake for humans and animals. In the present ... more Fluoride is an accumulative poison at high dose of intake for humans and animals. In the present study, the sorption of fluoride from aqueous solution has been investigated on synthetic hydrous ferric oxide (HFO), hydrous zirconium oxide (HZO) and hydrous zirconium(IV)-iron(III) oxide (HZFO) by batch mode experiments. Both HFO and HZFO were crystalline and HZO was amorphous in nature. The parametes studied were the effect of pH and sorption equilibriums. The results showed increase in fluoride-sorption with increasing pH from nearly 2.0 to 5.0, 4.6 and 6.8 for HFO, HZO and HZFO, respectively. Analysis of temperature dependent sorption data obtained at equilibrium solution pH 6.8 (+/- 0.2) has been described by the Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm model equations. The present sorption data fit, in general, found very well with the Langmuir and Redlich-Peterson models; and the data fit for HZFO and HFO found to increase, but for HZO the data found to decrease with increasing temperature. The computed thermodynamic parameters such as deltaG0, delltaH0 and deltaS0 from the Langmuir equilibrium constant (b, L/Umg) values show that the fluoride-sorption on HZFO was more spontaneous and endothermic process compared to HFO. The deltaH0 value obtained for fluoride adsorption on HZO indicates exothermic nature.
The adsorption/desorption behavior of Cd2+ and Cu2+ on/from nanostructured hydrous titanium (IV) ... more The adsorption/desorption behavior of Cd2+ and Cu2+ on/from nanostructured hydrous titanium (IV) oxide (NHTO) surfaces was studied at 30° C and pH 5.0 (±0.1). The pseudosecond-order kinetics model described the metal ion adsorption reactions with ...
Surface-altered hydrous iron(III) oxide incorporating cerium(IV) (CIHFO) was prepared and charact... more Surface-altered hydrous iron(III) oxide incorporating cerium(IV) (CIHFO) was prepared and characterised via modern analytical tools for applications in fluoride removal from groundwater. The material with a Fe : Ce ratio of 1.0 : 0.5 (mol : mol) calcined at 473 K shows 24.8 AE 0.5 mg F À g À1 adsorption capacity at pH 5.0–7.0 from a solution with a concentration of 15.0 mg L À1 ; the material was established to be microcrystalline ($5 nm) with a 140.711 m 2 g À1 surface area, irregular surface morphology and porous structure. The time-dependent fluoride adsorption capacities of CIHFO at 293, 303 and 313 K are well described by the pseudo-first order, pseudo-second order and Weber–Morris kinetic models, respectively. The adsorption reaction occurs via a film/boundary layer diffusion process. The very low Arrhenius activation energy (E a ¼ 0.026 kJ mol À1) indicates the high feasibility of fluoride adsorption over CIHFO. The equilibrium data fit better with the Freundlich and Redlich–Peterson (g < 1.0) isotherms than with the Langmuir isotherm, which suggests multilayer adsorption. The values of the Freundlich parameters, n ¼ 3.10, 4.47 and 7.57 and K F ¼ 8.58, 10.88 and 11.25 at 293, 303 and 313 K, respectively, indicate high affinity for fluoride. Thermodynamic analysis of the reaction equilibrium shows that the reaction is highly exothermic (DH 0 ¼ À25.924 and À36.279 kJ mol À1 for C i ¼ 25.0 and 35.0 mg L À1), whereas the negative DG 0 values indicate the spontaneous nature of the reaction. The fluoride adsorption over CIHFO occurs via ion-exchange that progresses to chemisorption. The presence of sulphate shows an adverse influence on fluoride adsorption by CIHFO, and the fluoride level of 2.4 g per L groundwater (9.05 mg F L À1) can be reduced below the permissible value.
Manganese oxide incorporated ferric oxide nanocomposite (MIFN), a novel adsorbent has been synthe... more Manganese oxide incorporated ferric oxide nanocomposite (MIFN), a novel adsorbent has been synthesized , characterized and explored for the removal of Cr(VI) from contaminated water. Surface elemental composition of semi-crystalline adsorbent was analyzed by SEM-EDX spectroscopy and was found to contain Fe (42.5%), Mn (8.1%) and O (49.4%), confirming Fe/Mn mole ratio of 5.0. BET surface area, particle diameter, pore size and total pore volume of the adsorbent were estimated as 186.28 m 2 g −1 , 5–7 nm, 81.2 A 0 and 0.31 cm 3 g −1 respectively. The adsorption of Cr(VI) was highly pH sensitive, and maximum adsorption was achieved within pH 2.0–3.0. Adsorption kinetics were described well by pseudo 2nd order model and were followed by both film diffusion as well as intra-particle pore diffusion mechanism. Langmuir isotherm was recognized to be the best fit model and maximum monolayer adsorption capacity was estimated as 47.84 mg g −1 for Cr(VI) at pH 3.0 at 303 K. Thermodynamic analysis revealed that the adsorption was highly favorable, spontaneous and endothermic in nature. Adsorption of Cr(VI) was strongly inhibited by phosphate and sulphate, whereas fluoride, carbonate, bicarbonate and silicate have no significant interference. Adsorption efficiency of the spent adsorbent (MIFN) could be rejuvenated around 78–80% by 1.0 M NaOH and subsequently be reused. The present study revealed that MIFN could be an efficient adsorbent for scavenging Cr(VI) from contaminated water because of its high adsorption capacity and reusability.
The synthetic bimetal iron(III)-titanium(IV) oxide (NHITO) used was characterized as hydrous and ... more The synthetic bimetal iron(III)-titanium(IV) oxide (NHITO) used was characterized as hydrous and nanostructured mixed oxide, respectively, by the Föurier transform infra red (FTIR), X-ray diffraction (XRD) pattern and the transmission electron microscopic (TEM) image analyses. Removal of As(III) and As(V) using the NHITO was studied at pH 7.0 (+/-0.1) with variation of contact time, solute concentration and temperature. The kinetic sorption data, in general, for As(III) described the pseudo-first order while that for As(V) described the pseudo-second order equation. The Langmuir isotherm described the equilibrium data (303 (+/-1.6)K) of fit was well with the Langmuir model. The Langmuir capacity (q(m), mg g(-1)) value of the material is 85.0 (+/-4.0) and 14.0 (+/-0.5), respectively, for the reduced and oxidized species. The sorption reactions on NHITO were found to be endothermic and spontaneous, and took place with increasing entropy. The energy (kJ mol(-1)) of sorption for As(III) and As(V) estimated, respectively, is 9.09 (+/-0.01) and 13.51 (+/-0.04). The sorption percentage reduction of As(V) was significant while that of As(III) was insignificant in presence of phosphate and sulfate. The fixed bed NHITO column (5.1 cm x 1.0 cm) sorption tests gave 3.0, 0.7 and 4.5L treated water (As content &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or = 0.01 mg L(-1)) from separate As(III) and As(V) spiked (0.35+/-0.02 mg L(-1)) natural water samples and from high arsenic (0.11+/-0.01 mg L(-1)) ground water, respectively when inflow rate was (0.06 L h(-1)).
International Journal of Green Nanotechnology, 2011
ABSTRACT Two different TiO2 particles with nanodimensions were prepared by sol-gel (TO-S) and low... more ABSTRACT Two different TiO2 particles with nanodimensions were prepared by sol-gel (TO-S) and low temperature chemical precipitation method (TO-P) from a TiCl4 precursor. As a result, the TO-S preparation was according to the “green chemistry” method because it did ...
... Natural Resource Accounting for Soils: Towards an Empirical Estimate of Costs of Soil Degrada... more ... Natural Resource Accounting for Soils: Towards an Empirical Estimate of Costs of Soil Degradation for India. KS Parikh and U. Ghosh. ... Check the EconPapers FAQ or send mail to . EconPapers is hosted by the Swedish Business School at Örebro University. ...
Fluoride is an accumulative poison at high dose of intake for humans and animals. In the present ... more Fluoride is an accumulative poison at high dose of intake for humans and animals. In the present study, the sorption of fluoride from aqueous solution has been investigated on synthetic hydrous ferric oxide (HFO), hydrous zirconium oxide (HZO) and hydrous zirconium(IV)-iron(III) oxide (HZFO) by batch mode experiments. Both HFO and HZFO were crystalline and HZO was amorphous in nature. The parametes studied were the effect of pH and sorption equilibriums. The results showed increase in fluoride-sorption with increasing pH from nearly 2.0 to 5.0, 4.6 and 6.8 for HFO, HZO and HZFO, respectively. Analysis of temperature dependent sorption data obtained at equilibrium solution pH 6.8 (+/- 0.2) has been described by the Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm model equations. The present sorption data fit, in general, found very well with the Langmuir and Redlich-Peterson models; and the data fit for HZFO and HFO found to increase, but for HZO the data found to decrease with increasing temperature. The computed thermodynamic parameters such as deltaG0, delltaH0 and deltaS0 from the Langmuir equilibrium constant (b, L/Umg) values show that the fluoride-sorption on HZFO was more spontaneous and endothermic process compared to HFO. The deltaH0 value obtained for fluoride adsorption on HZO indicates exothermic nature.
The adsorption/desorption behavior of Cd2+ and Cu2+ on/from nanostructured hydrous titanium (IV) ... more The adsorption/desorption behavior of Cd2+ and Cu2+ on/from nanostructured hydrous titanium (IV) oxide (NHTO) surfaces was studied at 30° C and pH 5.0 (±0.1). The pseudosecond-order kinetics model described the metal ion adsorption reactions with ...
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