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Lalhmunsiama,Lalchhingpuii,Nautiyal, B.P.,Tiwari, D.,Choi, S.I.,Kong, S.H.,Lee, S.M. Academic Press 2016 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.467 No.-
Hypothesis: Chitosan, naturally abundant biomaterial showed an insignificant affinity toward arsenate. The incorporation of organosilane could improve the physical and chemical properties of chitosan for the efficient removal of arsenate from aquatic environment. Experiment: The hybrid materials were obtained by grafting the natural biopolymer chitosan with 3-mercaptopropyl trimethoxysilane (CHMS) and trimethoxy-octylsilane (CHTS). The hybrid materials along with bare chitosan were characterized with SEM-EDX, FT-IR and BET specific surface area analyses and the solid materials were further employed in the efficient remediation of aqueous solutions contaminated with As(V) under batch and column reactor operations. Findings: The hybrid materials showed an extremely high percentage of As(V) removal compared to bare chitosan within a wide range of pH. As(V) was aggregated rapidly onto the solid surfaces and relatively high percent removal of As(V) was achieved in a wide range of As(V) initial concentrations. Moreover, As(V) was bound with, relatively, weaker forces and forming an 'outer sphere complexes' at the surface of solids. The presence of co-existing ions could not significantly affect the removal of As(V) from aqueous solutions. Furthermore, breakthrough data confirmed that these two hybrid materials possessed significantly high loading capacity of As(V) even under dynamic conditions.
Silane grafted chitosan in the remediation of aquatic environment contaminated with As(V)
( Lalhmunsiama ),정현훈,( Lalchhingpuii ),( Diwakar Tiwari ),이승목 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1
The trimethoxy-octylsilaneis grafted with chitosan under the inert atmosphere in acetic acid-ethanol solvent mixture. The grafted solid provide additional silane functionality along with the enhanced settling capacity makes material easy separable. The material is characterized by the SEM-EDX and FT-IR analysis. The materials are further employed in the remediation of aqueous solution contaminated with As(V) under the batch reactor operations. Batch studies show thatthe material possesses extremely high percent removal of As(V) comparing to the bare chitosan within the wide pH range i.e., pH 3 -10. The concentration dependence data is utilized to model Langmuir and Freundlich adsorption isotherms. Moreover, the kinetic data is fitted well to the pseudo-second-order rate equations; hence, the equilibriumsorption capacity is estimated.
( Lalhmunsiama ),이승목 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
The activated carbon (AC) was obtained from areca nut waste and it was further modified using succinic anhydrite under microwave reactor. The microwave-assisted process offers several advantages over the traditional methods in terms of selectivity in operation, fast and uniform irradiation, saving of time and energy and ease of control. The surface morphology of AC as well as modified AS were obtained by SEM image and the surface functional group present in the solid materials were discussed with FT-IR analysis. The synthesized material was further employed for the simultaneous removal of Hg(II) and phenol from aqueous solutions. Batch experiments showed that higher pH significantly favours the removal of Hg(II) whereas phenol removal was not affected by the change in pH of the solution. Moreover, various physicchemical parameters such as effect of initial concentrations, contact time and background electrolytes concentrations were also investigated.
Lalhmunsiama,Diwakar Tiwari,Seung-Mok Lee 대한환경공학회 2012 Environmental Engineering Research Vol.17 No.-
The two different dead biomasses were employed to obtain the activated carbon samples viz., rice hulls (AC-R) or areca nut waste (AC-N). Further, the surfaces of these activated carbons were modified with manganese to obtain the manganese coated activated carbons (MCAC-R and MCAC-N).These solids were assessed for their possible implication in the remediation of the aquatic environment contaminated with arsenic. The surface morphology of these solids was discussed with the scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDX) analysis. Various parametric studies viz., the effect of sorptive pH, concentration, background electrolyte concentration and contact time were studied under the batch reactor operations. The increase in sorptive pH (i.e., 2.0 to 10.0) and concentration (i.e., 1.0 to 10.0 mg/L) caused a great decrease in the percent removal of As(III) and As(V). Equilibrium modelling studies suggested that the data is fitted well to the Freundlich and Langmuir adsorption isotherms. The simultaneous presence of background electrolytes concentration (i.e., maximum 1,000 times NaNO3) could not significantly affect the uptake of these two ions which inferred that the sorption of As(III) and As(V) by these solids predominantly occurred through strong chemical forces and may ultimately form ‘inner-sphere’ complexes. The kinetic data was best fitted to the pseudo-first order kinetic model. Studies conferred that AC obtained from these agricultural by-products/wastes modified with manganese were found to be potential and promising solid materials in the attenuation of As(III) and As(V) from the aquatic environment.
Lalhmunsiama,Pawar, R.R.,Hong, S.M.,Jin, K.J.,Lee, S.M. Elsevier 2017 Journal of molecular liquids Vol.240 No.-
<P>Sericite powder was used as a substrate to immobilize the iron-oxide particles and it was encapsulated into beads using Na-alginate and Fe(III) ions by a simple cross-linking method to obtain iron-oxide modified sericite alginate beads (IMSA). The presence of iron oxide particle and other functional groups of alginate allows interaction of anionic arsenic species as well as the cationic Pb(II) ions with the IMSA beads; therefore, the material possess enhanced affinity towards these two highly toxic pollutants. The surface morphology and chemical composition of the beads were characterized by SEM-EDX analysis. Various functional groups present in the beads were identified by FT-IR analysis. Moreover, the iron content in the beads was obtained by US EPA 3050B method and the stability of immobilized iron was evaluated as a function of pH. The batch experiment showed that an increase in solution pH facilitate the uptake of Pb(II) whereas the As(V) removal found to decrease at higher pH. The simultaneous adsorption study showed that the As(V) removal was significantly high even at basic solution, which is perhaps, due to the presence of Pb(OH)(2) precipitates. The adsorption capacity of IMSA beads is evaluated using Langmuir adsorption isotherm and found to be 21.61 mg/g and 133.73 for As(V) and Pb(II), respectively. The adsorption kinetic data of As(V) fit well to pseudo second order kinetic model whereas Pb(II) showed a better fit to the pseudo first order kinetic model. Moreover, 100 times increase in the ionic strength of the solution did not show significant effect in the uptake of As(V) whereas Pb(II) removal was slightly suppressed. This study demonstrates that IMSA beads obtained by exploiting natural sericite, iron oxide and alginate are efficient and sustainable adsorbent for the removal of arsenic and lead from the aquatic environment. (C) 2017 Elsevier B.V. All rights reserved.</P>
Attenuation of radiotoxic ions from aqueous solutions using immobilized iron-oxide sand
( Lalhmunsiama ),( Jacqueline Lalthlengliani ),( Diwakar Tiwari ),이승목 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
The present work deals with the immobilization of iron oxide nanoparticles onto the surface of natural sand. The synthesized material was employed for the efficient removal of radiotoxic cesium and strontium from aqueous solutions. The surface morphology and elemental compositions of immobilized iron-oxide sand as well as bare sand were obtained by SEM-EDX analysis. Moreover, the materials were characterizedby XRD and FT-IR analyses. Reasonable amount of iron was loaded onto the sand surface and the immobilized iron particles were stable within a wide pH ranges i.e., pH 3.0 to 10.0. Batch experiments showed that increasing the sorptive pH significantly favours Cs(I) and Sr(II) removal and the equilibrium state sorption data under the concentration dependence study reasonably fit to Langmuir and Freundlich adsorption isotherm. Moreover, the breakthrough data were collected and the non-linear Thomas equation was utilized to determine the loading capacity of Cs(I) and Sr(II) using column packed with immobilized iron-oxide sand.