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Effect of coordination structure of aluminum on its activation from minerals and Oxisols during their acidification

Pedosphere 2024年第5期34卷 916-928页

作者： Kewei LI Yangxiaoxiao SHI Jackson Nkoh NKOH Jun JIANG renkou xu State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences University of Chinese Academy of Sciences

The types and contents of phyllosilicate minerals in soils play an important role in soil acidification,as soil acid buffering capacity varies with the composition of the phyllosilicate *** addition to aluminum-oxygen （Al-O） octahedrons,a certain number of Al-O tetrahedrons exist in phyllosilicate minerals due to the isomorphic substitution of silicon ion (Si4+) by aluminum ion (Al3+) in Si-O tetrahedrons of ***,the effect of the two coordination structures of Al on the release of Al during mineral acidification has not yet been ***,the differences in Al activation in phyllosilicate minerals and soils with different Al coordination structures were investigated through constant-p H experiments and27Al magic-angle spinning nuclear magnetic resonance （MAS-NMR） *** results of27Al MAS-NMR spectra showed that kaolinite contained Al-O octahedrons,phlogopite and illite contained Al-O tetrahedrons,and vermiculite composite contained both octahedral and tetrahedral *** p Hvermiculite composite>phlogopite>kaolinite,which was consistent with the orders of cation exchange capacity and content of tetrahedral Al of the *** to the rate constants,the Al release rates were in the order of phlogopite>illite>vermiculite composite>kaolinite at p H *** for phlogopite,the Al release rates in these minerals increased with decreasing suspension p ***,the Al release contents and rates were greater in phlogopite,illite,and vermiculite composite containing Al-O tetrahedrons than in kaolinite containing only Al-O *** Oxisols derived from basalt with different ages were selected for similar ***27Al MAS-NMR spectra of the Oxisols showed that the 0.01-million-year （Ma） Oxisol contained both octahedral and tetrahedral Al,while the 1.33-Ma Oxisol contained only Al-O *** contents of b

关键词： Al-O octahedrons Al-O tetrahedrons aluminum release exchangeable Al phyllosilicate minerals soil acidification

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Effects of urea and(NH_4)_2 SO_4 on nitrification and acidification of Ultisols from Southern China

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Journal of Environmental Sciences 2012年第4期24卷 682-689页

作者： Dell Tong renkou xu State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Graduate University of Chinese Academy of Sciences Beijing 100049China

The mechanisms for the effects of ammonium-based fertilizers on soil acidification in subtropical regions are not well understood. Two Ultisols collected from cropland and a tea garden in Anhui and Jiangxi Provinces in subtropical southern China, respectively, were used to study the effects of urea and （NH4）aSO4 on the nitrification and acidification of soils with incubation experiments. Nitrification occurred at very low pH with no N fertilizer added and led to lowering of the soil pH by 0.53 and 0.30 units for the soils from Jiangxi and Anhui, respectively. Addition of urea accelerated nitrification and soil acidification in both Ultisols; while nitrification was inhibited by the addition of （NH4）2SO4, and greater input of （NH4）2SO4 led to greater inhibition of nitrification. Ammonia-oxidizing bacteria （AOB） played an important role in nitrification in cropland soil under acidic conditions. Addition of urea increased the soil pH at the early stages of incubation due to hydrolysis and stimulated the increase in the AOB population, and thus accelerated nitrification and soil acidification. At the end of incubation, the pH of Ultisol from Jiangxi had decreased by 1.25, 1.54 and 1.84 units compared to maximum values for the treatments with 150, 300 and 400 mg/kg of urea-N added, respectively; the corresponding figures were 0.95, 1.25 and 1.69 for the Ultisol from Anhui. However, addition of （NH4）：SO4 inhibited the increase in the AOB population and thus inhibited nitrification and soil acidification. Soil pH for the treatments with 300 and 400 mg/kg of （NHn）2SOa-N remained almost constant during the incubation. AOB played an important role in nitrification of the cropland soil under acidic conditions. Addition of urea stimulated the increase in the AOB population and thus accelerated nitrification and soil acidification; while addition of （NH4）2SO4 inhibited the increase in the AOB population and thus inhibited nitrification.

关键词： ammonium-based fertilizer nitrification soil acidification ammonia-oxidizing prokaryotes

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Removal of Cu(Ⅱ) from acidic electroplating effluent by biochars generated from crop straws

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Journal of Environmental Sciences 2013年第4期25卷 652-658页

作者： xuejiao Tong renkou xu State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of Sciences College of Resource and Environment Nanjing Agricultural University

The removal efficiency of copper （Cu（Ⅱ）） from an actual acidic electroplating effluent by biochars generated from canola, rice, soybean and peanut straws was investigated. The biochars simultaneously removed Cu（Ⅱ） from the effluent, mainly through the mechanisms of adsorption and precipitation, and neutralized its acidity. The removal efficiency of Cu（Ⅱ） by the biochars followed the order： peanut straw char 〉 soybean straw char 〉 canola straw char 〉 rice straw char 〉〉 a commercial activated carbonaceous material, which is consistent with the alkalinity of the biochars. The pH of the effluent was a key factor determining the removal efficiency of Cu（Ⅱ） by biochars. Raising the initial pH of the effluent enhanced the removal of Cu（Ⅱ） from it. The optimum pyrolysis temperature was 400℃ for producing biochar from crop straws for acidic wastewater treatment, and the optimum reaction time was 8 hr.

关键词： adsorption biochar Cu(Ⅱ) removal electroplating effluent precipitation

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砖红壤中铬的溶出和外源三价铬的氧化转化

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土壤学报 2024年第4期61卷 1021-1030页

作者：施杨潇潇姜军李科伟徐仁扣土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所) 南京210008 中国科学院大学北京100049

砖红壤铬(Cr)的背景值和锰氧化物的含量均较高,当土壤中Cr溶出或者受到Cr(Ⅲ)污染,可能被氧化生成毒性较高的Cr(Ⅵ),从而对周围环境造成威胁。为考察砖红壤中Cr的环境风险,以云南、海南和广东采集的部分砖红壤为对象,研究土壤中Cr的溶... 详细信息

砖红壤铬(Cr)的背景值和锰氧化物的含量均较高,当土壤中Cr溶出或者受到Cr(Ⅲ)污染,可能被氧化生成毒性较高的Cr(Ⅵ),从而对周围环境造成威胁。为考察砖红壤中Cr的环境风险,以云南、海南和广东采集的部分砖红壤为对象,研究土壤中Cr的溶出和外源Cr(Ⅲ)的氧化。连二亚硫酸钠-柠檬酸钠-重碳酸钠法提取和电子探针扫描分析的结果表明,砖红壤中的Cr主要与铁氧化物和硅酸盐矿物结合,呈非活性状态。盐酸和柠檬酸的酸化和络合作用促进了Cr的溶出,但即使1 mol·L^(-1)的盐酸也仅使海南3和广东9砖红壤中3.68%和3.54%的Cr溶出。向砖红壤中添加Cr(Ⅲ)并培养42d,发现少量添加的Cr(Ⅲ)氧化为Cr(Ⅵ),但不同土壤中Cr(Ⅵ)的生成量与亚锰的净产生量不一致,说明土壤中Cr(Ⅲ)氧化生成的Cr(Ⅵ)可能会被土壤有机质重新还原为Cr(Ⅲ)。去除土壤有机质后,一次平衡实验中观察到外源添加的Cr(Ⅲ)氧化为Cr(Ⅵ),氧化量与土壤易还原锰的含量一致。随着溶液pH的增加,Cr(Ⅲ)的氧化量呈先上升后降低的趋势,在pH4.5时Cr(Ⅲ)氧化量达最大值,但Cr(Ⅲ)的氧化转化量在Cr(Ⅲ)添加量中的占比很小,外源Cr(Ⅲ)在土壤中氧化转化的风险也很低。虽然砖红壤的背景Cr和易还原锰的含量较高,但自然条件下Cr的溶解和Cr(Ⅲ)的氧化反应很难发生,Cr(Ⅲ)不易转化为Cr(Ⅵ),因此无需过度担忧砖红壤中Cr的环境风险。

关键词：砖红壤背景铬土壤铬溶解 Cr(Ⅲ)氧化铁锰氧化物

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Adsorption and desorption of Cu(Ⅱ) and Pb(Ⅱ) in paddy soils cultivated for various years in the subtropical China

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Journal of Environmental Sciences 2010年第5期22卷 689-695页

作者： Liang Ma renkou xu Jun Jiang State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China Graduate University of Chinese Academy of Sciences Beifing 100049 China

The adsorption and desorption of Cu（Ⅱ） and Pb（Ⅱ） on upland red soil,and paddy soils which were originated from the upland soil and cultivated for 8,15,35 and 85 years,were investigated using the batch *** study showed that the organic matter content and cation exchange capacity （CEC） of the soils are important factors controlling the adsorption and desorption of Cu（Ⅱ） and Pb（Ⅱ）.The 15-Year paddy soil had the highest adsorption capacity for Pb（Ⅱ）,followed by the 35-Year paddy *** the 35-Year paddy soil and 15-Year paddy soil adsorbed more Cu（Ⅱ） than the upland soil and other paddy *** 15-Year paddy soils exhibited the highest desorption percentage for both Cu（Ⅱ） and Pb（Ⅱ）.These results are consistent with the trend for the CEC of the soils *** high soil CEC contributes not only to the adsorption of Cu（Ⅱ） and Pb（Ⅱ） but also to the electrostatic adsorption of the two heavy metals by the *** desorption percentages for Cu（Ⅱ）（36.7% to 42.2%） and Pb（Ⅱ）（50.4% to 57.9%） were observed for the 85-Year paddy *** highest content of organic matter in the soil was responsible for the low desorption percentages for the two metals because the formation of the complexes between the organic matter and the metals could increase the stability of the heavy metals in the soils.

关键词： adsorption and desorption Cu(Ⅱ) Pb(Ⅱ) cultivation chronosequence paddy soil

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Adsorption of Cr(Ⅲ) from acidic solutions by crop straw derived biochars

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Journal of Environmental Sciences 2013年第10期25卷 1957-1965页

作者： Jingjian Pan Jun Jiang renkou xu State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of Sciences College of Resource and Environment Nanjing Agricultural University

Cr（Ⅲ） adsorption by biochars generated from peanut, soybean, canola and rice straws is investigated with batch methods. Adsorption of Cr（Ⅲ） increased as pH rose from 2.5 to 5.0. Adsorption of Cr（Ⅲ） led to peak position shifts in the FFIR-PAS spectra of the biochars and made zeta potential values less negative, suggesting the formation of surface complexes between Cr^3＋ and functional groups on the biochars. The adsorption capacity of Cr（Ⅲ） followed the order： peanut straw char 〉 soybean straw char 〉 canola straw char 〉 rice straw char, which was consistent with the content of acidic functional groups on the biochars. The increase in Cr^3＋ hydrolysis as the pH rose was one of the main reasons for the increased adsorption of Cr（Ⅲ） by the biochars at higher pH values. Cr（llI） can be adsorbed by the biochars through electrostatic attraction between negative surfaces and Cr^3＋, but the relative contribution of electrostatic adsorption was less than 5%. Therefore, Cr（Ⅲ） was mainly adsorbed by the biochars through specific adsorption. The Langumir and Freundlich equations fitted the adsorption isotherms well and can therefore be used to describe the adsorption behavior of Cr（Ⅲ） by the crop straw biochars. The crop straw biochars have great adsorption capacities for Cr（Ⅲ） under acidic conditions and can be used as adsorbents to remove Cr（Ⅲ） from acidic wastewaters.

关键词： biochar crop straw Cr(Ⅲ) adsorption functional groups zeta potential

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Effect of ionic strength on adsorption of As(Ⅲ) and As(V) on variable charge soils

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Journal of Environmental Sciences 2009年第7期21卷 927-932页

作者： xu renkou WANG Yong TIWARI Diwakar WANG Houyan State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanfing 210008 China Department of Chemistry Mizoram University Tanhril Campus Aizawl 796009 India Graduate University of Chinese Academy of Sciences Beifing 100049 China

The study was to investigate the adsorption behavior of arsenite （As（HI）） and arsenate （As（V）） on two variable charge soils, i.e., Haplic Acrisol and Rhodic Ferralsol at different ionic strengths and pH with batch methods. Results indicated that the amount of As（HI） adsorbed by these two soils increased with increasing solution pH, whereas it decreased with increasing ionic strength under the acidic condition. This suggested that As（Ⅲ） was mainly adsorbed on soil positive charge sites through electrostatic attraction under the acidic condition. Moreover, intersects of As（Ⅴ） adsorption-pH curves at different ionic strengths （a characteristic pH） are obtained for both soils. It was noted that above this pH, the adsorption of As（Ⅴ） was increased with increasing ionic strength, whereas below it the reverse trend was true. Precisely the intersect pH was 3.6 for Haplic Acrisol and 4.5 for Rhodic Ferralsol, which was near the values of PZSE （soil point of zero salt effect） of these soils. The effects of ionic strength and pH on arsenate adsorption by these soils were interpreted by the adsorption model. The results of zeta potential suggested that the potential in adsorption plane becomes less negative with increasing ionic strength above soil PZSE and decreases with increasing ionic strength below soil PZSE. These results further supported the hypothesis of the adsorption model that the potential in the adsorption plane changes with ionic strength with an opposite trend to surface charge of the soils. Therefore, the change of the potential in the adsorption plane was mainly responsible for the change of arsenate adsorption induced by ionic strength on variable charge soils.

关键词： arsenic adsorption ionic strength Haplic Acrisol Rhodic Ferralsol zeta potential

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Distribution of Manganese(Ⅱ) Chemical Forms on Soybean Roots and Manganese(Ⅱ) Toxicity

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Pedosphere 2019年第5期29卷 656-664页

作者： LIU Yuan LI Zhongyi xu renkou State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008 (China) Farmland Irrigation Research Institute Chinese Academy of Agricultural SciencesXinxiang 453002 (China) Key Laboratory of High-Efficient and Safe Utilization of Agriculture Water Resources Chinese Academy of Agricultural SciencesXinxiang 453002 (China)

Distribution of chemical forms of manganese(Ⅱ)(Mn(Ⅱ))on plant roots may affect Mn(Ⅱ)absorption by plants and toxicity of Mn(Ⅱ)to plants at its high *** chemical forms of Mn(Ⅱ)on soybean roots were investigated to determine the main factors that affect their distribution and relationship with Mn(Ⅱ)plant *** soybean roots were reacted with Mn(Ⅱ)in solutions,and Mn(Ⅱ)adsorbed on the roots was differentiated into exchangeable,complexed,and precipitated forms through sequential extraction with KNO3,EDTA,and *** exchangeable Mn(Ⅱ)content on the roots was the highest,followed by the complexed and precipitated Mn(Ⅱ)***(Ⅱ)toxicity to the roots was greater at pH 5.5 than at pH 4.2 due to the larger amount of exchangeable Mn(Ⅱ)at higher *** cations Al3+,La3+,Ca2+,Mg2+,and NH4+competed with Mn(Ⅱ)for cation exchange sites on the root surfaces and thus reduced exchangeable Mn(Ⅱ)on the roots,in the order Al3+,La3+>Ca2+,Mg2+>NH4+.Al3+ and La3+ at 100μmol L-1 decreased exchangeable Mn(Ⅱ)by 80%and 79%,respectively,and Ca2+ and Mg2+at 1 mmol L-1 decreased exchangeable Mn(Ⅱ)by 51%and 73%,*** anions oxalate,citrate,and malate reduced free Mn(Ⅱ)concentration in solution through formation of complexes with Mn(Ⅱ),efficiently decreasing exchangeable Mn(Ⅱ)on the roots;the decreases in exchangeable Mn(Ⅱ)on the roots were 30.9%,19.7%,and 10.9%,respectively,which was consistent with the complexing ability of these organic anions with Mn(Ⅱ).Thus,exchangeable Mn(Ⅱ)was the dominant form of Mn(Ⅱ)on the roots and responsible for Mn(Ⅱ)toxicity to *** coexisting cations and organic anions reduced the exchangeable Mn(Ⅱ)content,and thus they could alleviate Mn(Ⅱ)toxicity to plants on acid soils.

关键词： acidic soils cations exchangeable Mn(Ⅱ) organic anions plant micronutrient plant roots toxicity alleviation

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Heavy metal pollution characteristics and health evaluation of farmland soil in a gold mine slag area of Luoyang in China

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International Journal of Agricultural and Biological Engineering 2021年第5期14卷 213-221页

作者： Hui Wang Hao Zhang renkou xu College of Chemical and Pharmaceutical Engineering Henan University of Science and TechnologyLuoyang 471023China Analysis and Testing Center of Liming Research&Design Institute of Chemical Industry Co. Ltd.Luoyang 471001China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

The characteristics of eight heavy metals(lead,zinc,copper,nickel,chromium,cadmium,mercury and arsenic)in the surface soil of the historical slag area of the Au ore dressing plant in the South-West of Luoyang City were investigated and evaluated in terms of a pollution index,potential ecological hazards and health *** results showed that the average amounts of the heavy metals Pb,Zn and As in the soils of plots S3,S5,S7,S12 and S18 exceeded the soil pollution risk screening *** Mero comprehensive pollution index in plots S7,S12 and S18 was greater than 3,indicating severe *** severe pollution plot integrated the potential ecological risk index(RI)of each sampling point,which was in the order of RI_(S12)>RI_(S18)>RI_(S7)>RI_(S5)>RI_(S3).Among the heavy metals,Cd poses the greatest threat to ecological and human *** effects of heavy metals in soil on the single non-carcinogenic health risk index(HQ)and the non-carcinogenic total risk index through three exposure pathways were in the order of HQ_(Hg)

关键词： historical slag area heavy metals pollution assessment health assessment farmland soil ecological hazard

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Aluminum-Enhanced Proton Release Associated with Plasma Membrane H^+-Adenosine Triphosphatase Activity and Excess Cation Uptake in Tea (Camellia sinensis) Plant Roots

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Pedosphere 2018年第5期28卷 804-813页

作者： WAN Qing MI Yuhe YANG Yiyang xu renkou LI Xinghui Tea Research Institute Nanjing Agriculture University Institute of Leisure Agriculture Jiangsu Academy of Agricultural Sciences State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of Sciences

Cultivated tea(Camellia sinensis) plants acidify the rhizosphere, and Aluminum(Al) toxicity is recognized as a major limiting factor for plant growth in acidic soils. However, the mechanisms responsible for rhizosphere acidification associated with Al have not been fully elucidated. The present study examined the effect of Al on root-induced rhizosphere acidification, plasma membrane H^+-adenosine triphosphatase(H^+-ATPase) activity, and cation-anion balance in tea plant roots. The exudation of H^+from tea plant roots with or without Al treatment was visualized using an agar sheet with bromocresol purple. The H^+-ATPase activity of plasma membranes isolated from the roots was measured after hydrolysis using the two-phase partition system. The Al treatment strongly enhanced the exudation of H^+, and the acidification of tea plant roots by Al was closely associated with plasma membrane H^+-ATPase activity. The root plasma membrane H^+-ATPase activity increased with Al concentration. The Al content, amount of protons released, and H^+-ATPase activity were significantly higher in roots treated with Al than in those untreated. The results of the cation-anion balance in roots showed an excess of cations relative to anions, with the amount of excess cation uptake increasing with increasing Al concentrations. These suggest that Al-enhanced proton release is associated with plasma membrane H^+-ATPase activity and excess cation uptake. Findings of this study would provide insights into the contributing factors of soil acidification in tea plantations.

关键词： acidification aluminum toxicity cation-anion balance nutrient accumulation plant uptake rhizosphere soil acidity

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