Papers by Keyword: Adsorption

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Authors: Xian Hui Qiu
Abstract: Tannic acid, a natural polymer extracts from trees, was found to selectively depress galena while chalcopyrite was floated by xanthate. Micro-flotation studies, adsorption and Fourier transform infrared spectroscopy have been employed to investigate the mechanism. Micro-flotation studies shown that tannic acid can effectively depress galena while depress chalcopyrite weakly in the entire pH range. The adsorption results shown that the tannic acid adsorbed on chalcopyrite and galena surface influenced by the pH value, the higher the pH, the less of adsorption density. Tannic acid adsorb on galena through complexation with the lead ions, not with hydroxyl complex in the galena surface. Fourier transform infrared spectroscopy revealed that tannic acid interacted with lead ions by the hydroxyl groups on the phenol group. Tannic acid may be replace the hazardous inorganic depressants such as cyanide, dichromate and sulfur dioxide used in differential Cu-Pb sulfide separation.
1018
Authors: Bao Jian Liu, Shi Wang Liu, Tie Bing Liu, Jian Wei Mao
Abstract: Levulinic acid (LA) is a new versatile platform chemical derived from renewable non-food biomass. A major challenge in the purification of LA from biomass hydrolysate is the separation of LA and formic acid. A novel granular activated carbon (GAC) adsorption and separation of LA and formic acid were investigated in this work. Adsorption equilibria elucidated that LA preferentially adsorbed onto GAC than formic acid. Mixed solution of LA and formic acid was fed into the GAC packed-bed at 30°C, then formic acid was washed out from the column in a pure form with 60°C water and finally LA was effectively eluted with 95% (v/v) ethanol at 60°C. LA can be completely separated from formic acid by this simple GAC adsorption process with good yield and high purity.
1691
Authors: Wen Rui Zheng, Jing Li Xu
Abstract: The magnetite (Fe3O4) nanoparticles with immobilized metal affinity ligands were prepared for protein adsorption. First, magnetite nanoparticles were synthesized by hydrothermal method. Charged with Zn2+, the magnetic nanospheres were applied to adsorb bovine hemoglobin (BHb). The morphology and magnetic properties of magnetic nanospheres were investigated by TEM. These magnetic nanospheres modified with metal ligands can be used efficiently in protein affinity separation and purification.
1841
Authors: Meng Wang, Fan Yong Yan, Dong Lei Cao, Xin Yu Song
Abstract: A novel supramolecular smart poly(N-isopropylacrylamide-co-tetra(5-hexenyloxy)-p- tert-butylcalix[4]arene) (P(NIPAAm-co-Calix)) hydrogel was synthesized by free radical polymerization of N-isopropylacrylamine(NIPAAm) and modified calix[4]arene. The swelling behaviours and ionic adsorption capacity were studied. It is found that the polymeric network of the P(NIPAAm-co-Calix) hydrogel is characterized by an open structure with more pores and higher swelling ratio compared to the PNIPAAm hydrogel. The adsorption abilities of heavy toxic metal ions (Ni2+, Cu2+, Pb2+, Cd2+) for P(NIPAAm-co-Calix) hydrogels and PNIPAAm hydrogel were different and depend on the temperature. This could provide a theoretical basis for the intelligent response mechanism to stimulate research of supramolecular hydrogel.
325
Authors: Zhi Yong Ji, Jun Sheng Yuan, Xiao Fu Guo, Jun Wang, Ling Li
Abstract: Based on preparing high purity powdered lithium ion-sieve precursor LiMn2O4, using lithium carbonate and manganese carbonate as raw materials, through roasting at high temperature of 800°C, laminar lithium ion-sieve precursor was prepared by commixing poly (vinyl chloride) (PVC) and powdered precursor in DMF (N, N-dimethylformamide) as solvent, and then powder and lithium ion-sieve flat sheet membrane was obtained through washing with HCl solution respectively. Their adsorption capacity and morphology was also characterized. The results show that both powdered lithium ion-sieve and laminar one have high adsorption capacity and selectivity for Li in solutions, and the effect of their retest is good. All these can provide a good foundation for the further study on lithium ion-sieve flat sheet membrane and lithium extraction from seawater.
144
Authors: O. Assowe, Olivier Politano, Vincent Vignal, Patrick Arnoux, B. Diawara
Abstract: The interaction of water molecules on a nickel surface was studied using ReaxFF (reactive force field) molecular dynamics. This approach was originally developed by van Duin et al. to study the hydrocarbon chemistry and the catalytic properties of organic compounds. To our knowledge, this method has not been used to study the corrosion processes of nickel exposed to water, which is what we set out to achieve in the present investigation. To do so, calculations were first performed using ReaxFF in order to reproduce certain well-known properties of pure nickel and nickel-water systems. This allowed us to study the adsorption of a single water molecule interacting with an optimized nickel surface. We also investigated the interaction of 405 molecules of water (ρ=0.99 g.cm-3) on the (100), (110) and (111) surfaces of a single crystal of nickel at 300 K. The results show that a water bilayer is adsorbed on nickel surfaces: the first water layer is directly bonded to the surface, whereas the molecules in the first and second layers are held together by hydrogen bonds.
139
Authors: Sana Yaqub, Nurhayati Mellon, Azmi Mohamad Shariff
Abstract: The presence of carbon dioxide (CO2) in natural gas stream is a critical problem; besides causing corrosion it also reduces the energy contents and heating value of natural gas. Various separation techniques are available to separate CO2 from natural gas, such as metal organic framework (MOF), covalent organic framework (COF) and Covalent Organic Polymer (COP) adsorbents. The criteria of adsorbent selection that need to be fulfilled include high adsorption capacity, high selectivity of CO2 and hydrothermal stability at operating conditions. COPs are crystalline porous materials having high CO2 capacity and selectivity in the presence of water vapors. However, the research on COP material development is new and scarce information is available in literature. In this prospect, the paper highlights the different types of COPs, their basic constituents and the adsorption capacities.
237
Authors: Kai Li Zhang, Li Wei Xie, Li Hong Huang, Zong Qiang Zhu, Liang Liang Tan
Abstract: Compared with the treatment of heavy metal waste water by bamboo charcoal and modified bamboo charcoal. The mainly types and methods of modified bamboo charcoal adsorption of pollution water is introduced. some important factors that effecting the bamboo charcoal and modified bamboo charcoal adsorption of heavy metal pollution were described in detail, summarizes the desorption method of the specific adsorbent and adsorption mechanism.
188
Authors: Byeoung Ku Kim, Young Seak Lee, Seung Kon Ryu, Byung Joo Kim, Soo Jin Park
Abstract: In this work, to introduce polar functional groups on carbon surfaces, activated carbon fibers (ACFs) were treated by nitric acid in order to enhance the adsorption capacity of propylamine which was one of toxic gases in cigarette smoke. It was found that the polar functional groups were predominantly increased up to 2.0 M of nitric acid, resulting in the increase of total surface acidity. It was found that the adsorption amount of propylamine of the modified ACFs was increased around 17% after a nitric acid treatment. From the XPS results, it was observed that propylamine was reacted with strong or weak polar (acidic) groups, such as COOH, -COO or OH existed on the ACF surfaces.
211
Authors: Zhi Bin Li, Ji Wei Hu, Su Ming Duan, Xian Fei Huang, Miao Jia, Yi Wang, Chun Liu, Jin Luo
Abstract: The affecting factors and kinetic characteristics of antimony (Sb) adsoption onto a type of the coconut shell activated carbon were investigated in this study. The results showed that: the Sb adsorption obeyed the pseudo-second-order kinetics equation, and the coefficients of determination (R2) were higher than 0.97, inferring that this process was mainly the monolayer chemical adsorption. With the reduction of the particle size, the adsorption capacity of activated carbon gradually increased. With the increase of temperature, activated carbon adsorption of antimony content increased gradually, but on the whole the temperature had a limited effect on the adsorption of activated carbon. Effect of the solution pH on antimony adsorption onto the activated carbon was mainly divided into the following two stages: with a pH value of 1 to 3, antimony removal rate was about 60%, and with a pH value of 5 to 11, the removal rate was about 20%.
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