The flotation and adsorption behaviors of dodecyltrimethylammonium chloride（DTAC） and cetyltrimethylammonium chloride（CTAC） on diaspore and kaolinite were studied.Solution depletion methods were used to determine ...The flotation and adsorption behaviors of dodecyltrimethylammonium chloride（DTAC） and cetyltrimethylammonium chloride（CTAC） on diaspore and kaolinite were studied.Solution depletion methods were used to determine adsorption isotherms.Fluorescence probe test along with Zeta potential measurement was also conducted for further investigation into the adsorption of quaternary amines at the mineral-water interface.The results show that the flotation recovery of kaolinite decreases with an increase in pH when DTAC and CTAC are used as collectors,while diaspore is on the contrary.As the carbon chain length of the collectors increases,the flotation recoveries of minerals increase.However,the increment rate of kaolinite is significantly lower than that of diaspore.In the low surfactant concentration range,the cationic surfactants adsorb readily on diaspore surfaces just due to electrostatic interactions.As for kaolinite surfaces,ion exchange process also exists.With a further increase in surfactant concentration,the adsorption was ascribed to the hydrophobic association of chain-chain interactions.Micro-polarity of mineral surfaces study shows that CTAC has a better hydrophobic characteristic than DTAC.Larger aggregates are formed with CTAC on diaspore than on kaolinite in the same solution concentration.The results also indicate that the chain length of cationic surfactants has a greater influence on the adsorption of diaspore than on kaolinite,which is consistent with the flotation result.展开更多
To evaluate the role of kaolinite and variable charge soils on the hydrolytic reaction of Al, the hydrolysis of Al ions in suspensions of a kaolinite and an Oxisol influenced by organic anions was investigated using c...To evaluate the role of kaolinite and variable charge soils on the hydrolytic reaction of Al, the hydrolysis of Al ions in suspensions of a kaolinite and an Oxisol influenced by organic anions was investigated using changes of pH, Al adsorption, and desorption of pre-adsorbed Al. Kaolinite and the Oxisol promoted the hydrolytic reaction of Al above a certain initial Al concentration (0.1 mmol L-1 for kaolinite and 0.3 mmol L-1 for the Oxisol). The Al hydrolysis accelerated by kaolinite and the Oxisol increased with an increase in initial concentration of Al and was observed in the range of pH from 3.7 to 4.7 for kaolinite and 3.9 to 4.9 for the Oxisol. The acceleration of Al hydrolysis also increased with the increase of solution pH, reached a maximum value at pH 4.5, and then decreased sharply. Al hydrolysis was promoted mainly through selective adsorption for hydroxy-Al. Soil free iron oxides compensated a portion of the soil negative charge or masked some soil surface negative sites leading to a decrease in Al adsorption, which retarded acceleration to some extent. For the Oxisol organic anions increased the proportion of adsorbed Al3+ in total adsorbed Al with the increase in soil negative surface charge and eliminated or reduced the acceleration of Al hydrolysis. Different organic anions inhibited the hydrolysis of Al in the order: citrate > oxalate > acetate (under initial pH of 4.5). The formation of Al-organic complexes in solution also inhibited the hydrolysis of Al.展开更多
The effect of background anion on cation exchange reactions, suchas Na-Ca and Na-Cu exchange reac- tions, on montmorillonites has beenstudied, but the results are not always clear and discrepancies existin the literat...The effect of background anion on cation exchange reactions, suchas Na-Ca and Na-Cu exchange reac- tions, on montmorillonites has beenstudied, but the results are not always clear and discrepancies existin the literature. In this study, the exchange of zinc (Zn^2+) forsodium (Na^+) on Wyoming montmorillonite was investigated at 298 deg.K using Cl^-, ClO_4^-, NO_3^-, Oac^-, and SO_4~2- solution media at aconstant total metal charge concentration of 0.02000 mol_c L^-1.Results indicated that the clay CEC values were essential similar forCl^-, ClO_4^-, NO_3^- and SO_4~2- solution media with an average CECof 0.856±0.008 mol_c kg^-1; in an OAc^- solution the clay CEC wasmuch higher than that in other anion media.展开更多
The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particle...The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particles was smiliar to that of kaolinite clay. On the surface of BS, both toluene insoluble organic matter and structural OH group are detected at the same time. The surface characteristics imparted a bi-wettable nature to the BS. As a result, the BS is able to stabilize fine water emulsion in the bitumen phase. The organic matter associated with BS is a possible factor of the fouling on catalyst and equipment.展开更多
This paper studies the adsorption isotherm curves of four amino acids (glycine, aspartic acid, glutamic acid and lysine) and the effects of existences of different concentrations of Cu(II) on them. Both the adsorption...This paper studies the adsorption isotherm curves of four amino acids (glycine, aspartic acid, glutamic acid and lysine) and the effects of existences of different concentrations of Cu(II) on them. Both the adsorption isotherm of the amino acids on the kaolinite and that when the copper ion Cu (II) exists belong to the Langmuir type. The slopes of these adsorption isotherm increase with the increasing concentrations of Cu(II) added. It can be explained in terms of formation of the type(I) ternary surface complexes in these systems. The regular pattern of the effects of copper ion Cu(II) on the adsorption isotherm of amino acids on the kaolinite is identical with that of its effects on the exchange and adsorption percentage E (%)-pH on the kaolinite in the same system.展开更多
基金Projects (50974134,50804055) supported by the National Natural Science Foundation of ChinaProject (2005CB623701) supported by the National Basic Research Program of China
文摘The flotation and adsorption behaviors of dodecyltrimethylammonium chloride（DTAC） and cetyltrimethylammonium chloride（CTAC） on diaspore and kaolinite were studied.Solution depletion methods were used to determine adsorption isotherms.Fluorescence probe test along with Zeta potential measurement was also conducted for further investigation into the adsorption of quaternary amines at the mineral-water interface.The results show that the flotation recovery of kaolinite decreases with an increase in pH when DTAC and CTAC are used as collectors,while diaspore is on the contrary.As the carbon chain length of the collectors increases,the flotation recoveries of minerals increase.However,the increment rate of kaolinite is significantly lower than that of diaspore.In the low surfactant concentration range,the cationic surfactants adsorb readily on diaspore surfaces just due to electrostatic interactions.As for kaolinite surfaces,ion exchange process also exists.With a further increase in surfactant concentration,the adsorption was ascribed to the hydrophobic association of chain-chain interactions.Micro-polarity of mineral surfaces study shows that CTAC has a better hydrophobic characteristic than DTAC.Larger aggregates are formed with CTAC on diaspore than on kaolinite in the same solution concentration.The results also indicate that the chain length of cationic surfactants has a greater influence on the adsorption of diaspore than on kaolinite,which is consistent with the flotation result.
基金Project supported by the National Natural Science Foundation of China (No. 40271062).
文摘To evaluate the role of kaolinite and variable charge soils on the hydrolytic reaction of Al, the hydrolysis of Al ions in suspensions of a kaolinite and an Oxisol influenced by organic anions was investigated using changes of pH, Al adsorption, and desorption of pre-adsorbed Al. Kaolinite and the Oxisol promoted the hydrolytic reaction of Al above a certain initial Al concentration (0.1 mmol L-1 for kaolinite and 0.3 mmol L-1 for the Oxisol). The Al hydrolysis accelerated by kaolinite and the Oxisol increased with an increase in initial concentration of Al and was observed in the range of pH from 3.7 to 4.7 for kaolinite and 3.9 to 4.9 for the Oxisol. The acceleration of Al hydrolysis also increased with the increase of solution pH, reached a maximum value at pH 4.5, and then decreased sharply. Al hydrolysis was promoted mainly through selective adsorption for hydroxy-Al. Soil free iron oxides compensated a portion of the soil negative charge or masked some soil surface negative sites leading to a decrease in Al adsorption, which retarded acceleration to some extent. For the Oxisol organic anions increased the proportion of adsorbed Al3+ in total adsorbed Al with the increase in soil negative surface charge and eliminated or reduced the acceleration of Al hydrolysis. Different organic anions inhibited the hydrolysis of Al in the order: citrate > oxalate > acetate (under initial pH of 4.5). The formation of Al-organic complexes in solution also inhibited the hydrolysis of Al.
文摘The effect of background anion on cation exchange reactions, suchas Na-Ca and Na-Cu exchange reac- tions, on montmorillonites has beenstudied, but the results are not always clear and discrepancies existin the literature. In this study, the exchange of zinc (Zn^2+) forsodium (Na^+) on Wyoming montmorillonite was investigated at 298 deg.K using Cl^-, ClO_4^-, NO_3^-, Oac^-, and SO_4~2- solution media at aconstant total metal charge concentration of 0.02000 mol_c L^-1.Results indicated that the clay CEC values were essential similar forCl^-, ClO_4^-, NO_3^- and SO_4~2- solution media with an average CECof 0.856±0.008 mol_c kg^-1; in an OAc^- solution the clay CEC wasmuch higher than that in other anion media.
基金Financially supported by the Opening Fund of National Key Laboratory of State Heavy Oil University of Petroleum+1 种基金 Beijing (2003-04) and the Scientific Research Foundation (SRF) for the Returned Overseas Chinese Scholars (ROCS) State Education Minis
文摘The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particles was smiliar to that of kaolinite clay. On the surface of BS, both toluene insoluble organic matter and structural OH group are detected at the same time. The surface characteristics imparted a bi-wettable nature to the BS. As a result, the BS is able to stabilize fine water emulsion in the bitumen phase. The organic matter associated with BS is a possible factor of the fouling on catalyst and equipment.
文摘This paper studies the adsorption isotherm curves of four amino acids (glycine, aspartic acid, glutamic acid and lysine) and the effects of existences of different concentrations of Cu(II) on them. Both the adsorption isotherm of the amino acids on the kaolinite and that when the copper ion Cu (II) exists belong to the Langmuir type. The slopes of these adsorption isotherm increase with the increasing concentrations of Cu(II) added. It can be explained in terms of formation of the type(I) ternary surface complexes in these systems. The regular pattern of the effects of copper ion Cu(II) on the adsorption isotherm of amino acids on the kaolinite is identical with that of its effects on the exchange and adsorption percentage E (%)-pH on the kaolinite in the same system.
