Rapid urbanization has led to extensive land-use changes,particularly in developing countries.This research is aimed to investigate the role of land use and its effect on soil and water quality in Ziarat watershed foc...Rapid urbanization has led to extensive land-use changes,particularly in developing countries.This research is aimed to investigate the role of land use and its effect on soil and water quality in Ziarat watershed focusing on four land uses:forest,pasture,cultivated and urban development.Soil samples were taken from a depth of 0-30 cm on each land use and were analyzed by completely randomized split-plot design in two geographical directions.Results showed that bulk density(BD),electrical conductivity(EC),pH,calcium carbonate equivalent(CCE),and soil particle density(DS) of the soil samples in pastures,cultivated and urban areas increased and the mean weight diameter(MWD),soil porosity(F),organic carbons(OC),total nitrogen(TN),exchangeable cations(Ca 2+,Mg 2+,K +,Na +),cation exchange capacity(CEC) and soil microbial respirations(SMR) decreased,respectively in comparison with the forest soils.For water quality evaluations,sodium adsorption ratio(SAR),electrical conductivity(EC),pH,total dissolved solids(TDS),bicarbonate(HCO 3),chloride(Cl),total hardness(TH),calcium(Ca 2+),potassium(K +),sodium(Na +) and magnesium(Mg 2+) were investigated in two areas:Nahrkhoran and Abgir stations.Results showed that the concentration of TDS,EC and HCO 3 in Naharkhoran station is higher than that in Abgir station.On the other hand,the concentration of TDS,EC and HCO 3 in Abgir station are the relatively higher due to its location.Total hardness had the same trend during the study years except in the last three years;however,TH showed an increase of 25% TH in Naharkhoran for the last two years.Cl,K + and SAR in Naharkhoran station increased by 61%,22%,78% and 56% respectively,in comparison with Abgir station.This study demonstrated that the trend of soil degradation and mismanagement of land use may increase the frequency of urban floods and human health problems.展开更多
The adsorption capacity of Pb(Ⅱ) on litchi pericarps was investigated as a function of temperature,pH,and adsorbent dose using batch experiments.The experimental data obtained were evaluated using adsorption equilibr...The adsorption capacity of Pb(Ⅱ) on litchi pericarps was investigated as a function of temperature,pH,and adsorbent dose using batch experiments.The experimental data obtained were evaluated using adsorption equilibrium isotherms and a kinetic model.Additionally,the removal of Pb(Ⅱ) in leachate of litchi pericarps was also evaluated.The results show that litchi pericarps exhibit a high adsorption capacity to Pb(Ⅱ),with the maximum removal efficiency occurring at a temperature of 25 ℃,a pH of 6.0-7.0 and an adsorbent dosage of 10 g/L.Langmuir and Freundlich isotherms and the pseudo-second-order kinetic model can all fit the equilibrium adsorption satisfactorily,with correlation coefficients(R^2) of 0.9935,0.9918 and 1.0,respectively.An average removal efficiency of 66.65% is found for Pb(Ⅱ) in leachate of litchi pericarps.展开更多
Constructed wetlands （CWs） are engineered systems that utilize natural systems including wetland vegetations, soils, and their associated microbial assemblages to assist in treating wastewater. The kinetic adsorptio...Constructed wetlands （CWs） are engineered systems that utilize natural systems including wetland vegetations, soils, and their associated microbial assemblages to assist in treating wastewater. The kinetic adsorption of ammonium nitrogen （NH＋-N） by CW substrate materials such as blast furnace slag （BFS）, zeolite, ceramsite, vermiculite, gravel, paddy soil, red soil, and turf, was investigated using batch experiments and kinetic adsorption isotherms. Both Freundlich and Lang- muir isotherms could adequately predict the NH＋-N adsorption process. The maximum adsorption capacities of NH＋-N, estimated from the Langmuir isotherm, ranked as： zeolite （33 333.33 mg kg^-1） 〉 turf （29274.01 mg kg^-1） 〉 BFS （5000 mg kg^-1） 〉 vermiculite （3333.33 mg kg^-1） 〉 gravel （769.23 mg kg^-1） 〉 paddy soil （588.24 mg kg^-1） 〉 red soil （555.56 mg kg^-1） 〉 ceramsite （107.53 mg kg^-1）. Some properties of the substrate materials, including bulk density, specific gravity, hydraulic conductivity, uniformity coefficient （K60）, curvature coefficient （Co）, organic matter, pH, exchangeable （or active） Cu, Fe, Zn and Mn, total Cu, and Fe, Mn, Zn, Cd, Pb and Ca, had negative correlations with NH＋-N adsorption. Other properties of the substrate materials like particle diameter values of D10, 030 and 060 （the diameters of particle sizes of a substrate material at which 10%, 30% and 60%, respectively, of the particles pass through the sieve based on the accumulative frequency）, cation exchange capacity （CEC）, exchangeable （or active） Ca and Mg, and total K and Mg had positive correlations with NH＋-N adsorption. In addition, active K and Na as well as the total Na had significant positive correlations with NH＋-N adsorption. This information would be useful for selection of suitable substrate materials for CWs.展开更多
基金National Key Research and Development Program of China(No.2016YFB0700504)Science and Technology Commission of Shanghai Municipality(No.15DZ2260300 and No.16DZ2260600)Young Teacher Program in Shanghai Higher Institution(No.37-0101-14-203)~~
文摘Rapid urbanization has led to extensive land-use changes,particularly in developing countries.This research is aimed to investigate the role of land use and its effect on soil and water quality in Ziarat watershed focusing on four land uses:forest,pasture,cultivated and urban development.Soil samples were taken from a depth of 0-30 cm on each land use and were analyzed by completely randomized split-plot design in two geographical directions.Results showed that bulk density(BD),electrical conductivity(EC),pH,calcium carbonate equivalent(CCE),and soil particle density(DS) of the soil samples in pastures,cultivated and urban areas increased and the mean weight diameter(MWD),soil porosity(F),organic carbons(OC),total nitrogen(TN),exchangeable cations(Ca 2+,Mg 2+,K +,Na +),cation exchange capacity(CEC) and soil microbial respirations(SMR) decreased,respectively in comparison with the forest soils.For water quality evaluations,sodium adsorption ratio(SAR),electrical conductivity(EC),pH,total dissolved solids(TDS),bicarbonate(HCO 3),chloride(Cl),total hardness(TH),calcium(Ca 2+),potassium(K +),sodium(Na +) and magnesium(Mg 2+) were investigated in two areas:Nahrkhoran and Abgir stations.Results showed that the concentration of TDS,EC and HCO 3 in Naharkhoran station is higher than that in Abgir station.On the other hand,the concentration of TDS,EC and HCO 3 in Abgir station are the relatively higher due to its location.Total hardness had the same trend during the study years except in the last three years;however,TH showed an increase of 25% TH in Naharkhoran for the last two years.Cl,K + and SAR in Naharkhoran station increased by 61%,22%,78% and 56% respectively,in comparison with Abgir station.This study demonstrated that the trend of soil degradation and mismanagement of land use may increase the frequency of urban floods and human health problems.
基金Project(51208173)supported by the National Natural Science Foundation of ChinaProject(ZR2014EEM005)supported by the Natural Science Foundation of Shandong Province,China
文摘The adsorption capacity of Pb(Ⅱ) on litchi pericarps was investigated as a function of temperature,pH,and adsorbent dose using batch experiments.The experimental data obtained were evaluated using adsorption equilibrium isotherms and a kinetic model.Additionally,the removal of Pb(Ⅱ) in leachate of litchi pericarps was also evaluated.The results show that litchi pericarps exhibit a high adsorption capacity to Pb(Ⅱ),with the maximum removal efficiency occurring at a temperature of 25 ℃,a pH of 6.0-7.0 and an adsorbent dosage of 10 g/L.Langmuir and Freundlich isotherms and the pseudo-second-order kinetic model can all fit the equilibrium adsorption satisfactorily,with correlation coefficients(R^2) of 0.9935,0.9918 and 1.0,respectively.An average removal efficiency of 66.65% is found for Pb(Ⅱ) in leachate of litchi pericarps.
基金Supported by the National Natural Science Foundation of China (Nos. 40871110 and 30828005)the National Water Pollution Control and Management Special Project of China (No. 2009ZX07102-003)+1 种基金the Special Project of Science and Technology of Guangdong Province,China (No. 2008A080800028)the Supporting Project of Science and Technology of Guangzhou City,China (No. 2008Z1-E621)
文摘Constructed wetlands （CWs） are engineered systems that utilize natural systems including wetland vegetations, soils, and their associated microbial assemblages to assist in treating wastewater. The kinetic adsorption of ammonium nitrogen （NH＋-N） by CW substrate materials such as blast furnace slag （BFS）, zeolite, ceramsite, vermiculite, gravel, paddy soil, red soil, and turf, was investigated using batch experiments and kinetic adsorption isotherms. Both Freundlich and Lang- muir isotherms could adequately predict the NH＋-N adsorption process. The maximum adsorption capacities of NH＋-N, estimated from the Langmuir isotherm, ranked as： zeolite （33 333.33 mg kg^-1） 〉 turf （29274.01 mg kg^-1） 〉 BFS （5000 mg kg^-1） 〉 vermiculite （3333.33 mg kg^-1） 〉 gravel （769.23 mg kg^-1） 〉 paddy soil （588.24 mg kg^-1） 〉 red soil （555.56 mg kg^-1） 〉 ceramsite （107.53 mg kg^-1）. Some properties of the substrate materials, including bulk density, specific gravity, hydraulic conductivity, uniformity coefficient （K60）, curvature coefficient （Co）, organic matter, pH, exchangeable （or active） Cu, Fe, Zn and Mn, total Cu, and Fe, Mn, Zn, Cd, Pb and Ca, had negative correlations with NH＋-N adsorption. Other properties of the substrate materials like particle diameter values of D10, 030 and 060 （the diameters of particle sizes of a substrate material at which 10%, 30% and 60%, respectively, of the particles pass through the sieve based on the accumulative frequency）, cation exchange capacity （CEC）, exchangeable （or active） Ca and Mg, and total K and Mg had positive correlations with NH＋-N adsorption. In addition, active K and Na as well as the total Na had significant positive correlations with NH＋-N adsorption. This information would be useful for selection of suitable substrate materials for CWs.
