Kinetic research on the sorption of aqueous cadmium on carbonate hydroxyapatite     

Yu LIU Huanyan XU 《中国地球化学学报》2006,25(B08):104-105

The sorption of aqueous cadmium on carbonate-hydroxyapatite （CHap） is a complicated non-homogeneous solid/water reaction, From kinetic point of view, it can be described by two stages： at the earlier stage, reaction rate is so fast that its kinetic course is intricate, and at the later stage, the rate of reaction becomes slow and the process of reaction accords with one order reaction kinetic equation. Experimental results show that the relationship between reaction rate constant kl and temperature T accords to Arrhenius Equation, and the activation energy of sorption （Ea） is 6.075 J/mol and frequency factor （A） is 220 s^-1. At the same time, reaction rate constant kl increases with decreasing Cd^2＋ initial concentration, on the contrary, with increasing pH and CHap dosage.  相似文献   

Form changes and bio-effect of cadmium in the alkaline soil operated by inorganic salts     

Zuwei WANG Xin LIU Hui ZHANG 《中国地球化学学报》2006,25(B08):86-86

Four soluble inorganic salts were used to examine their influences upon cadmium forms in the alkaline soil and the contents of cadmium absorbed by plants. After KCl solution added in the soil, the contents of effective form of cadmium in the soil increased from 28% to 122%, carbonate form decreased from 2% to 47%, iron-manganese oxidation form increased from 20% to 150%. As to the organic combination form, when the KCl solution of lower concentration was added in the soils, the organic combination form contents of cadmium would decrease, while the KCl solution of higher concentration was added in the soils, the organic combination form contents of cadmium would increase. After CaCl2 solution was added in the soils, the contents of effective form of cadmium in the soils increased from 7% to 33%, the carbonate form contents of cadmium decreased from 10% to 60%, the contents of the iron-manganese oxidation form of cadmium increased from 5% to 90%, the organic combination form of cadmium increased from 5% to 73%. After KH2PO4 solution was added in the soils, the contents of effective form of cadmium in the soils decreased from 20% to 46%, the carbonate form contents of cadmium decreased from 14% to39%, the contents of the iron-manganese oxidation form of cadmium increased from14% to 95%, the organic combination form of cadmium increased from 5% to 65%. After K2CO3 solution was added in the soil, the effective form contents of cadmium decreased from 5% to 22%, the carbonate form contents of cadmium increased from 12% to 64%, the contents of organic combination form of cadmium in the soils were similar to those of the carbonate form, increasing by 3%-38%. The content variation of the iron-manganese oxidation form of cadmium was slight after K2CO3 solution was added in the soils.  相似文献   

Removal of Cadmium Ions from Aqueous Solution by Silicate-incorporated Hydroxyapatite          下载免费PDF全文

SHI Hebin ZHONG Hong LIU Yu DENG Jinyang 《《地质学报》英文版》2007,81(3):517-522

This article reports a preliminary research on silicate-incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate-incorporated hydroxyapatite was prepared by coprecipitation and calcining, and silicate was incorporated into the crystal lattice of hydroxyapatite by partial substitution of phosphate. The amount of cadmium ions removed by silicate-incorporated hydroxyapatite was significantly elevated, which was 76% higher than that of pure hydroxyapatite. But the sorption behavior of cadmium ions on silicate-incorporated hydroxyapatite was similar to that of pure hydroxyapatite. Morphological study revealed that silicate incorporation confined the crystal growth and increased the specific surface area of hydroxyapatite, which were in favor of enhancing the cadmium ion sorption capacity of the samples. Incorporation of silicate into hydroxyapatite seems to be an effective approach to improve the environmental property of hydroxyapatite on removal of aqueous cadmium ions.  相似文献   

云南金顶超大型铅锌矿区镉的地球化学特征及其环境效应   总被引：11，自引：0，他引：11  

李航  叶霖  肖唐付  潘自平  何立斌  孙嘉龙  宁增平  彭景权 《矿物学报》2007,27(2):225-232

云南金顶铅锌矿是镉元素富集区,采矿活动导致镉元素释放出来进入地表环境造成镉污染。矿区不同岩石中镉分布差异比较大,围岩中镉含量范围在50×10-6~650×10-6之间,平均310×10-6,原生矿中镉含量范围14×10-6~2800×10-6,平均767×10-6,氧化矿中镉含量范围110×10-6~8200×10-6,平均1661×10-6,其平均值最高。氧化矿是镉元素的主要载体和释放源。淋滤实验表明矿石易氧化而释放出镉等有害元素,滤出元素可以迅速发生沉淀或被沉淀物包裹,其能力表现为Zn>Pb>Cd。研究结果表明,矿区下游江河段水体中隔的平均值为15.7μg/L,悬浮物中镉平均值为49.3 mg/kg,沉积物中镉平均值为203.7 mg/kg。矿区富镉岩石和矿物的自然风化是造成江水体和沉积物中镉污染的直接原因,对流域水生态环境造成潜在危害。  相似文献   

某冶炼厂附近农田镉污染调查与对策   总被引：5，自引：2，他引：3  

闭向阳  马振东 《地质科技情报》2003,22(2):87-90

对遭受某铜矿冶炼厂镉污染的湖北省某镇约30km^2的农田土壤进行了调查,对土壤耕作层与亚耕层以及污染源(废气、废水和炉渣)中全量Cd和有效态Cd含量的系统测定结果表明：未受Cd污染、受轻度污染及受中度污染的土壤面积分别占3．6％,82．1％,14．3％;土壤中全量Cd及有效态Cd含量的分布规律均表现为西灌区＞东灌区＞灌间区;土壤耕作层与亚耕层中全量Cd含量的差异不大,而有效态Cd则主要富集于土壤耕作层中;受土壤pH值的影响,Cd在污染区土壤中的活化率低于远离冶炼厂未受污染的农田对照区。该镇农田的Cd污染主要来源于某铜矿冶炼厂的废气和废水,而炉渣的污染相对较小。运用生态方法治理该镇农田的Cd污染具有一定的可行性和适用性,值得研究利用。  相似文献   

甲基异丁基酮负载泡塑富集—原子吸收测定岩矿中痕量金银铊镉   总被引：4，自引：4，他引：4  

陈金武  曾法刚 《岩矿测试》1993,12(2):85-88

研究了多种负载泡塑对Au、Ag、Ti、Cd的富集行为。提出了在HCI-KI-抗坏血酸介质中用甲基异丁基酮(MIBK)负载泡塑同时萃取,然后用2％硫脲-1％HCl解脱的富集方法,并采用火焰原子吸收连续测定地质样品中痕量Au、Ag、Tl和Cd,方法的测定下限(μg/g)分别为:0.2g、0.05、0.20和0.04。  相似文献   

NaDDC泡塑富集火焰原子吸收法测定天然水中痕量镉     

汪模辉  陈强 《矿物岩石》1990,10(4):109-112

本文将NaDDC—泡塑用于分离富集天然水中的痕量镉。对富集和洗脱条件、共存离子的影响及干扰的消除作了详细研究。试验结果表明,在pH8—10的氨性环境,以柠檬酸和酒石酸作掩蔽剂,NaDDC—泡塑可定量富集天然水中的痕量镉。每克NaDDC—泡塑对镉的饱和富集容量高达45mg。富集于NaDDC—泡塑上的镉用2％磺基水杨酸在沸水浴中定量洗脱后,可直接用火焰AAS法测定。  相似文献   

4l0哌啶树脂分离富集－原子吸收测定化探样品中痕量镉     

李玉珍  陈德勋 《岩矿测试》1995,(4):285-287

研究了４１０哌啶树脂对Ｃｄ的吸附行为，在２％～２０％ＨＣＩ介质中［ＣｄＣｌ＿３］￣－被树脂吸附，采用４％～３０／ＨＮＯ＿３溶液可以解脱Ｃｄ，回收率在９６％以上。测定了Ｃｄ在该树脂上的分配系数为５４９０，对含Ｃｄ０．０６７μｇ／ｇ的标样ＧＳＲ－３平行测定６次，相对标准偏差为９．５％。方法用于化探样品中０．０Ｘ×１０￣－６级Ｃｄ的测定，结果满意。  相似文献   

计算极谱法同时测定镉镍的研究   总被引：1，自引：0，他引：1  

佘振宝  梁中 《岩矿测试》1993,12(1):46-49

采用普通极谱仪与计算机联机技术,用卡尔曼滤波处理以KSCN为支持电解质的Cd~(2+)和Ni~(2+)混合溶液的示波极谱重叠波。实验表明,极谱可逆波具有较好的加和性,可采用计算极谱方法对多组分(尤其是难以分开的重叠波)进行同时测定。  相似文献   

北京城近郊区土壤对镉的吸附特征研究     

许春雪潘小菲  王亚平王迪民 《岩矿测试》2005,24(3):161-166

在0．1～1200mg／L不同Cd^2＋浓度条件下，进行了五个地区土壤对重金属Cd^2＋的静态吸附实验。土壤分别采自于北京城近郊丰台区北天堂村、大兴区庑殿村、通州区永乐店镇、海淀区四季青乡和朝阳区来广营乡五个地区。实验结果表明：常温常压下，土壤对Cd^2＋的吸附量与加入到土壤中的Cd^2＋总量呈现出一定的正相关。四季青、永乐店的重粉质壤土、庑殿的中粉质壤土及北天堂的轻壤土对Cd^2＋的吸附量S与土壤溶液中的平衡浓度C都基本满足直线拟合。在相同外源Cd^2＋浓度下，土壤对Cd^2＋的吸附量为：庑殿的中粉质壤土〉四季青的重粉质壤土〉永乐店的重粉质壤土〉来广营的重粉质壤土〉北天堂的轻壤土。在所拟实验条件下，土壤对镉的吸附很大程度上受到土壤有机质含量、土壤的粘粒和粉粒所占比例的控制，而酸碱度pH和氧化还原电位Eh对类型不同的土壤的吸附影响效应不很明显。  相似文献