Browsing by Author "Y.C. Sharma"

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Adsorption of cadmium(II) from aqueous solutions by an indigenous clay mineral
(2006) Y.C. Sharma; V. Srivastava
Removal of cadmium, a priority pollutant, has been investigated by a locally available clay mineral, China clay. The removal depends on initial concentration of cadmium in solution and higher removal has been obtained in lower concentration ranges. The removal increased from 41.0 to 80.3% by decreasing the concentration of cadmium in solution from 2.0×10 -4 to 0.5×10-4 M at 6.5 pH, 100 rpm and 0.01 M NaC104 ionic strength. The pH of the solution plays an important role in the removal of cadmium. Rate of the removal was calculated by Lagergren's model and was found to be 5.10×10-2 min-1 in optimum conditions. The process of removal proceeds with intraparticle diffusion and the value of the coefficient of intraparticle diffusion was found to be 3.25×10-10 cm2 s-1. The parameters can be used for designing a plant for treatment of Cd(II) rich water and wastewater economically.
Alumina nanoparticles for the removal of Ni(II) from aqueous solutions
(2008) Y.C. Sharma; V. Srivastava; S.N. Upadhyay; C.H. Weng
Alumina nanoparticles were developed by the sol-gel method and were used for the removal of Ni(II) ions from aqueous solutions. The nanoparticles were characterized by TEM and XRD. Nanoparticles of alumina were then used for removal of Ni(II) ions from aqueous solutions of nickel. The nanosize of the adsorbent was confirmed by TEM and XRD. Removal (%) was found to be dependent on the initial concentration of nickel, and maximum removal was found to be 96.6% at 25 mg/L Ni(II). The removal increased from 99 to 99.6% by decreasing the initial concentration from 75 to 25 mg/L. Equilibrium time was found to be 120 min. As expected, higher removal was obtained at higher adsorbent dose. The removal was governed by first-order kinetics, and the value of the rate constant of adsorption was found to be 1.83 × 10-2 min-1 at 25 mg/L and 25°C. The removal was found to be pH dependent, and maximum removal was found to be at pH 8.0. The adsorption process was endothermic in nature. The experimental data fit well the Langmuir and Freundlich isotherms. Constants of the two isotherm equations were determined. Thermodynamic studies for the present process were performed by determining the values of ΔG̊, ΔH̊, and ΔS̊ at different temperatures. © 2008 American Chemical Society.
An economically viable removal of methylene blue by adsorption on activated carbon prepared from rice husk
(2011) Y.C. Sharma; Uma; S.N. Upadhyay
Application of an agricultural waste material, rice husk, has been investigated for preparation of activated carbon. The rice husk-activated carbon (RHAC) was successfully utilised for the removal of a cationic dye, methylene blue (MB) from aqueous solutions. The activated carbon was prepared in presence of ZnCl2 as an activating agent under inert nitrogen atmosphere. RHAC was characterised for surface area, pore structural parameters, and point zero charge (pHZPC). The activated carbon was further characterised by Fourier transformation infrared (FT-IR) spectrometer, X-ray diffractometer (XRD), and scanning electron microscope (SEM). The effect of different parameters such as contact time and initial concentration, adsorbent dose, and temperature on removal of the dye from aqueous solutions was investigated. The experimental data fitted well in both the Freundlich and Langmuir isotherm models. The maximum adsorption capacity for MB was found to be 9.73mgg-1 at 303K. During the study of effect of adsorbent dose, almost a 100% removal was achieved at a higher dose of RHAC. Most of the experiments were carried out at an initial concentration of MB of 60mg/L and at 303K. Different thermodynamic parameters, viz., changes in free energy (G°), enthalpy (H°), and entropy (S°) have also been determined to explain feasibility of the process of removal. The sorption of MB on RHAC was found to be feasible, spontaneous, and endothermic in nature. © 2010 Canadian Society for Chemical Engineering.
Engineering data for optimization of preparation of activated carbon from an economically viable material
(2010) Y.C. Sharma; Uma; F. Gode
Activated carbon has been a fascinating material, especially for the removal of different pollutant species from gaseous and aqueous phases. Activated carbons can be prepared from a variety of cellulosic materials. This study is an effort to investigate the characteristics of activated carbon prepared from an agricultural waste material, coconut coir. The surface area and porosity of the activated carbon were determined by nitrogen adsorption isotherms at 77 K. The pore size distribution was determined by a N2 adsorption isotherm that shows the pore width, surface area, and total pore volume of the activated carbon. The BET surface area of synthesized activated carbon was found to be 205.27 m2·g-1. After activation, both micropores and a small volume of mesopores are formed in the product. Thermogravimetric analysis was used to monitor the course of pyrolysis of coconut coir and ZnCl2-impregnated coconut coir. Important physicochemical properties of the activated carbon were confirmed by Fourier transform IR spectroscopy and X-ray diffractometry. © 2010 American Chemical Society.
Highly selective ppm level LPG sensors based on SnO2-ZnO nanocomposites operable at low temperature
(Elsevier B.V., 2023) Snehal D. Patil; Harshal A. Nikam; Y.C. Sharma; Ram Sagar Yadav; Dinesh Kumar; Akhilesh Kumar Singh; D.R. Patil
The nanoscaled SnO2, ZnO and SnO2-ZnO nanocomposite powders were prepared by microwave aided ultrasonication technique by employing centrifuge for the collection of dried powder of the materials. The fabrication of thick films of the pure ZnO and SnO2-ZnO nanocomposite powders were made by simple screen printing technique. The crystallographic phases of the pure ZnO and SnO2 doped ZnO are hexagonal in nature. The average crystallite size of 0 (pure), 1, 3, 5, 7 and 9 wt% of SnO2 doped ZnO films was found to be 30.2, 30.3, 109.7, 37.9, 36.8 and 45.6 nm, respectively. The SEM micrographs depict the porous nature of the thick films. The EDS analysis reveals that the pure ZnO and SnO2 doped ZnO films are oxygen deficient and show a semiconducting nature. The symmetric I-V characteristics depict the ohmic and non-ohmic natures of the thick films. The electrical resistivity measurements indicate a negative temperature coefficient of resistance. The gravimetric analysis shows that the average thickness of the pure ZnO thick film is 28 µm. The LPG response versus doping concentration plot suggests that the (1 wt%) SnO2 doped ZnO thick film exhibits crucial response to 100 ppm LPG at 50 °C and 100 °C. Therefore, the SnO2 doped ZnO thick film can be applicable in the field of LPG sensing with rapid response and recovery. © 2022 Elsevier B.V.
Kinetics studies of synthesis of biodiesel from waste frying oil using a heterogeneous catalyst derived from snail shell
(2012) Ashish Birla; Bhaskar Singh; S.N. Upadhyay; Y.C. Sharma
Waste frying oil was used to produce biodiesel using calcined snail shell as a heterogeneous base catalyst. Trans esterification reactions were carried out and the yield and conversion of the product were optimized by varying the methanol to oil molar ratio, catalyst amount, reaction temperature, and time. A biodiesel conversion of 99.58% was obtained with a yield of 87.28%. The reaction followed first order kinetics. The activation energy (E A) was 79kJ/mol and the frequency factor (A) was 2.98×10 10min -1. The fuel properties of the biodiesel were measured according to ASTM D 6751 and found to be within the specifications. Snail shell is a novel source for the production of heterogeneous base catalyst that can be successfully utilized for synthesis of biodiesel of high purity. © 2011 Elsevier Ltd.