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Kinetic model for sorption of divalent heavy metal ions on low cost minerals
Murari Prasad,Aseem Chawla,Rishta Goswami,Shweta Ranshore,Ankita Kulshreshtha,Akhouri Sudhir Kumar Sinha 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.2
A mathematical model is proposed that could predict the kinetic parameters for adsorption of divalent heavy metal ions (lead, copper and zinc) onto low-cost adsorbents such as pyrophyllite and rock phosphate using experimental data. The experiments were conducted with the initial concentrations of metal ions ranging from 10mg/L to 100mg/L. The mathematical model is based on the application of the Redlich-Peterson isotherm to mass transfer across the film surrounding the adsorbent. The developed non-linear sorption kinetic (NSK) mathematical model was solved using numerical integration by the trapezoidal method in Microsoft Excel along with the SOLVER function to obtain the best simulated values of the Redlich-Peterson constants A, B, r, the order of reaction n, and the film transfer coefficient α. Dissolution followed by precipitation was found to be the most probable mechanism responsible for heavy metal ion uptake by rock phosphate, while for pyrophyllite physical adsorption was governing mechanism at low concentrations (<100mg/L). The values of parameters A, B, r and α lie in the ranges of 0.015-23.2, 0.00003-3.09, 0.072- 1, and 0.000057-52.8 [(L/mg)(n−1)/min], respectively, under different experimental conditions.
Hari Prasad Uppara,Sunit Kumar Singh,Nitin Kumar Labhsetwar,Mudiyaru Subrahmanya Murari,Harshini Dasari 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.7
The synthesis of binary mixed oxide Ce-Hf (CH), ternary mixed oxide Ce-Hf-Ru (CHR), and Ce-Hf-Mg (CHM) has been attempted using the PVP-assisted sol-gel method. The structural and surface morphology of the prepared catalysts were investigated and studied for the generation of superoxides (O2 )/peroxides (O2 2) species and availability of lattice oxygen (O) during soot oxidation reactions. The successfully incorporated Hf4+/Mg2+ into ceria (CH, CHM) enhances the redox potential sites on nano-flake morphology, thus produces more oxygen vacancies (□). However, Ru4+/Hf4+ was not doped into the ceria structure in CHR catalyst; it showed lesser structural distortions generating fewer oxygen vacancies. In addition, it was observed that better performing catalysts should possess lower oxidation temperature and be catalytically stable. Indeed, the ternary oxide CHR featured excellent catalytic properties when compared with the others. However, CHM was found structurally and catalytically stable with self-regenerative capability even after the repeated soot oxidation experiments. Thus, the possible soot oxidation mechanism has been proposed on the prepared catalysts.
Xu, Huan-Yan,Prasad, Murari,Wang, Peng Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.4
Schorl modified by $H_2SO_4$ has been successfully developed to enhance schorl-catalyzed Fenton-like reaction for removal of phenol in an aqueous solution. The phenol removal percentage can be increased from 4% to 100% by the system of modified schorl and $H_2O_2$. Batch experiments indicate that the percent increases in removal of phenol by increasing the dosage of catalyst, temperature and initial concentration of $H_2O_2$. The results of XRD, FT-IR and SEM suggest that no new phases are formed after removal of phenol by modified schorl. ICP-AES results reveal that more dissolution of iron results in higher catalytic oxidant activity in the system of modified schorl and $H_2O_2$. Besides minor adsorption, mineral-catalyzed Fenton-like reaction governs the process.
Huan-Yan Xu,Murari Prasad,Peng Wang 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.4
Schorl modified by H₂SO4 has been successfully developed to enhance schorl-catalyzed Fenton-like reaction for removal of phenol in an aqueous solution. The phenol removal percentage can be increased from 4% to 100% by the system of modified schorl and H₂O₂. Batch experiments indicate that the percent increases in removal of phenol by increasing the dosage of catalyst, temperature and initial concentration of H₂O₂. The results of XRD, FT-IR and SEM suggest that no new phases are formed after removal of phenol by modified schorl. ICP-AES results reveal that more dissolution of iron results in higher catalytic oxidant activity in the system of modified schorl and H₂O₂. Besides minor adsorption, mineralcatalyzed Fenton-like reaction governs the process.