支持电解质对水钠锰矿表面Cu2 吸附-解吸的影响

氧化锰矿物是土壤和沉积物中的重要组分,在土壤中的含量一般不超过10g kg-1。但其颗粒细小,常以膜状赋存于土壤颗粒表面,并在土壤界面的化学反应中起着重要作用;其电荷零点(PZC)低、比表面积大、负电荷量多,对某些重金属元素有吸附固定作用,影响并决定着它们在土壤和沉积物中的浓度、形态、化学行为及生物毒性[1~10]。氧化锰矿物对重金属离子的吸附特性一直是许多土壤与环境科学工作者研究的重点,其吸附顺序一般为:Pb>Cu>Mn>Co>Zn>Ni>Ca>Mg,并普遍认为是专性吸附[3~5]。其专性吸附机理常有配位、内层交换、水解—吸附、表面络合和同晶替代等理论[3]。在土壤pH通常范围内,表面带正电     

土壤中的氧化锰对酚类化合物的氧化降解作用

本文研究了砖红壤和红壤中的氧化锰对１０种有毒酚化合物的氧化降解作用及氧化锰与酚化合物之间的氧化还原动力学，结果表明，土壤中氧化锰对某些有毒酚化合物具有氧化降解作用，各种酚化合物氧化降解的难易与其本身性质和分子结构有关。土壤中的氧化锰的还原溶解和氢醌的卖化均符合一级反应动力学方程。介质ｐＨ的降低有利于反应的进行，两种土壤中的氧化锰不溶解反应对（Ｈ＾＋）的级数为０．１６，氢醌除与氧化锰发生氧化还原反应     

几种土壤铁锰结核对Cr(Ⅲ)的氧化特性Ⅱ.pH、离子强度、温度等因素的影响

以我国几种土壤中铁锰结核为材料 ,研究了不同pH、离子强度和温度条件下氧化锰矿物对Cr(Ⅲ )的氧化。结果表明 :随着体系pH的降低、离子强度的增加以及温度的升高 ,供试铁锰结核对Cr(Ⅲ )的氧化量增加 ,这除了与其氧化还原反应本身消耗H 有关外 ,还与氧化锰矿物表面电荷性质和电位变化、共存的氧化铁矿物有关。而上述因素的变化导致N2 1、N4 1号样氧化Cr(Ⅲ )的增幅比N5 1号样的大 ,则可能与氧化锰矿物的结晶程度、晶体构造和铁锰结核中Mn(Ⅳ )的含量等有关     

黄土高原旱地连续施用锰肥的土壤效应研究

采用连续浸提形态分级方法，研究了连续施用锰肥17a后锰的土壤化学特性变化。结果表明：经过长期连续施用锰肥，土壤全锰和DTPA—Mn含量增加不多。土壤DTPA—Mn含量随试验时间的延长呈增加趋势，施锰土壤有效锰提高不多，土壤DTPA—Mn含量只增加了0．4～1．7mgkg^-1。土壤中的锰主要以矿物态存在，占土壤全锰含量的比例为87．3％～91.8％。碳酸盐态、氧化锰态和紧结有机态锰占全锰的比例相当，土壤中各形态锰按含量大致呈矿物态〉碳酸盐态〉氧化锰态〉紧结有机态〉松结有机态〉交换态的顺序。施入土壤的锰肥有91．1％～98．6％进入碳酸盐结合态、氧化锰结合态、紧结有机态和矿物态，只有很少一部分仍留在有效态锰库中。交换态和松结有机态锰对土壤锰的有效性起着主要作用，可以反映土壤锰的供给状况，碳酸盐态和紧结有机态锰不能反映土壤锰的有效性。     

几种土壤锰结构对Cr（Ⅲ）的氧化与锰矿物类型

以几种土壤锰结核为实验材料，研究了不同氧化锰对Cr(Ⅲ）的氧化特性。结果表明，供试锰结核对Cr(Ⅲ）的氧化能力大小顺序为N1－1＞N4－1＞N2－1＞N5－1，与他们所含量还原性锰含量顺序不一致。换算的还原性锰对Cr(Ⅲ）的氧化后，则其顺序为N4－1＞N2－1＞N1－1＞N5－1。由组成供试锰结核的主要氧化锰矿物得知，对Cr(Ⅲ）的氧化能力：钠水锰矿＞锂硬锰矿＞钙锰矿。这可能与氧化锰矿物的结晶程度、晶体构造和Mn(Ⅳ）含量的差异以及Cr(Ⅲ）在氧化锰表面的吸附位置有关。     

土壤中含钾矿物的研究--Ⅰ.含钾矿物中钾的形态及其释放

土壤中的含钾矿物含有大量的钾,这些钾素是植物营养的可能给源,早已引起农业化学家的注意。土壤中的主要含钾矿物有黑云母、白云母、伊利石和长石等。研究土壤中含钾矿物的种类及其性质,对充分利用土壤中的钾素及合理施用钾肥具有一定的指导意义。本文着重研究四种含钾矿物的一些物理化学特性。     

环境矿物材料在土壤环境修复中的应用研究进展

环境矿物材料(包括天然矿物及改性和人工合成矿物等材料)已经广泛应用到有机污染、重金属污染及病毒污染土壤中。本文在回顾环境矿物材料研究进展的基础上重点综述了环境矿物材料在修复重金属、有机污染物和病毒污染土壤中的应用。其中,重点论述了硅酸盐矿物、磷灰石、金属氧化物等天然矿物材料,以及改性和人工合成矿物材料在修复重金属污染土壤中的应用效果及其机理;同时阐述了硅酸盐矿物和金属氧化物在修复有机污染和病毒污染土壤中的应用效果及其机理;最后展望其主要研究方向。     

矿物对溶解性有机质及其不同组分的吸附作用

溶解性有机质(Dissolved Organic Matter,DOM)在土壤矿物表面的吸附控制着其在土壤中的迁移,会影响土壤/矿物对重金属、有机污染物等的传质过程[1～3]。已往资料揭示,土壤中黏土矿物是DOM的重要吸附质;但迄今,有关DOM在不同类型黏土矿物表面吸附的差异及机制尚很不清楚。另外,不同DOM组分在土壤矿物上的吸附各异,土壤矿物对DOM不同成分的吸附具有选择性;因此分离DOM不同组分,分别研究其在土壤矿物上的吸附有助于揭示DOM与土壤矿物的结合机理,但该研究尚待深化。此外,目前研究中DOM多以土壤中提取的为主[4],对于因污泥农用等农业管理措施而从外部引入土壤的DOM的研究还较     

几种土壤组分对原有土壤中锌的富集能力的研究

本文研究了我国部分自然土壤中氧化铁、氧化锰及有机质三种组分对原有土壤中锌的富集能力。并比较了不同土壤类型中各组分对锌的富集能力,探讨了土壤环境条件主要为pH对组分富集能力的影响。结果表明,土壤中这三种组分其单位含量对锌的富集能力为:氧化锰>氧化铁>有机质;三:种组分对锌的富集能力在土壤间的变化以氧化铁最为明显,其顺序为石灰性土壤>中性土壤>酸性土壤;土壤pH对土壤氧化铁富集锌能力的影响也很明显。氧化铁对锌的富集分配比例为:酸性土壤<5,中性土壤5—15,石灰性土壤≥15,各土壤组分对锌的富集容量次序为:氧化铁>有机质>氧化锰,氧化铁中,晶形铁>无定形铁。     

土壤含钾矿物的释钾研究进展

介绍土壤中含钾矿物的类型、结构特点、钾素含量与钾素释放的关系,区分了含钾矿物在土壤中的构成及分布特点,同时对国内外关于含钾矿物钾素释放规律的研究状况,钾素释放的作用机理、动力学特性,以及影响土壤含钾矿物钾素释放的因素做了综述。     

铁锰氧化矿物添加对土壤镉有效态及生物效应的影响

利用铁锰氧化矿物对土壤中镉的吸附特性,研究了镉污染的土壤中施加铁锰氧化矿物后对土壤中镉的有效态及植物有效性的影响,结果表明：在土壤中添加铁锰氧化矿物后,土壤中镉的有效态含量明显降低;铁锰氧化矿物对土壤中镉的吸附在十天左右达到平衡;在相同的加入量,软锰矿比针铁矿的吸附效果好;利用数量化理论预测法,建立了氧化矿物加入量和土壤中镉含量及理化性质之间关系的预测模型,预测精度较好;通过温室土培试验,几种植物添加铁锰氧化矿物后镉的总量明显降低,证明添加铁锰氧化矿物可以明显降低土壤中镉的生物有效性。     

Effect of iron oxide on phosphate sorption by calcite and calcareous soils

Pure calcite (AR grade CaCO₃) was treated with ferrous perchlorate solution to give a surface coating of iron (Fe) oxide. Maximum sorption (x_m) of phosphate (P) by the calcite increased from 18.2 to 160 mg P kg^?1 as the amount of coating increased from 0.00 to 16.0 g Fe₂O₃, kg^?1 CaCO₃. Evidence for Fe oxide coatings on carbonate minerals in two Sudanese soils was obtained by optical microscopy and electron-probe microanalysis. The relative contributions of carbonate and Fe oxide minerals, and Fe oxide coatings to P sorption in these soils were calculated, based on an assumed model of oxide distribution. Separate-phase Fe oxide was the major contributor (30–40%) to P sorption in the soils; the Fe oxide coatings on carbonate minerals were only minor contributors (< 6%), and the contribution of uncoated carbonate minerals was found to be negligible (<1 %). These results suggest a very minor role for carbonate minerals, even when coated with Fe oxide, in the sorption of P by these calcareous, Sudanese soils.     

应用穆斯堡尔谱和X射线法研究红壤性水稻土的氧化铁矿物

应用穆斯堡尔谱和X射线法分析研究红壤性水稻土的氧化铁矿物,研究结果表明,红壤性水稻土的氧化铁矿物组成、特性及其形成转化与起源土壤具有明显的差异。水稻土的成土条件不利于赤铁矿的形成。红壤的粘粒氧化铁矿物以赤铁矿和高铝替代(>20摩尔%)的针铁矿为主。经淹水种稻后,赤铁矿逐渐被转化为低铝替代的针铁矿或其它形态氧化铁。渗育型水稻土P层的赤铁矿含量比相应的母土低,其针铁矿铝替代量较其它水型的水稻土高。而潴育型水稻土W层和潜育型水稻土G层粘粒氧化铁矿物均以针铁矿为主,其铝同晶替代量低(<15摩尔%),且颗粒细小,结晶度较低。这些结果反映了水稻土的成土条件和发生特点,同时对水稻土发生分类具有重要的意义。     

Composition and properties of poorly ordered minerals in Welsh soils. II. Phosphate adsorption and reactivity towards NaF solution

Eleven horizons of acidic soils developed from Lower Palaeozoic sedimentary rocks in mid Wales contained varying amounts of poorly ordered minerals. In nine of these over 70% of the phosphate adsorption capacity was attributed to poorly ordered minerals. Iron oxide with substituted Al, and a separate Al oxide, together accounted for the phosphate adsorption of the poorly ordered fraction. Aluminium-substitution had no major effect on the adsorption capacity of Fe oxide, but since Al occurred in both active minerals it masked the effect of Fe on phosphate adsorption in simple correlations. The relative contribution of the two mineral forms to phosphate adsorption varied widely between soils. Aluminium as a substituent in Fe oxide and in 'free' oxide form was responsible for the soils' reactivity towards NaF, but no distinction could be made between these poorly ordered forms. For certain horizons both poorly ordered Al and Si were correlated with OH⁻ release, but Al oxides were more important than silicates.     

Iron oxide and clay minerals and their relation to colours of red and yellow podzolic soils near Sydney,Australia

The iron oxide and clay minerals in some typical red and yellow podzolic soils from New South Wales have been investigated by X-ray diffraction and infra-red spectroscopy. The dominant iron oxide mineral is goethite containing about 13–14 mol % AlOOH, this being the mineral which gives the yellow soils their characteristic colour. The red soils also contain finely divided hematite which masks the colour of the goethite. Lepidocrocite was not detected in any of the soils examined. The dominant clay minerals are kaolinite and dioctahedral interstratified illite-smectite, the latter being more concentrated in the finer clay fractions, especially in soils developed on calcareous greywacke. In the red podzolic soil developed on Ashfield shale, illite-smectite is strongly interlayered with well-ordered aluminous material. Dickite occurs in this soil.     

Sorption and desorption of cobalt by soils and soil components

The sorption of Co by individual soil components was studied at solution Co concentrations that were within the range found in natural soil solutions. Soil-derived oxide materials sorbed by far the greatest amounts of Co although substantial amounts were also sorbed by organic materials (humic and fulvic acids). Clay minerals and non-pedogenic iron and manganese oxides sorbed relatively little Co. It is considered that clay minerals are unlikely to have a significant influence on the sorption of Co by whole soils. Cobalt sorbed by soil oxide material was not readily desorbed back into solution and, in addition, rapidly became non-isotopically exchangeable with solution Co. In contrast, Co was relatively easily desorbed from humic acid and a large proportion of the Co sorbed by humic acid remained isotopically exchangeable. Cobalt sorbed by montmorillonite was more easily desorbed than that sorbed by soil oxide but less easily than that sorbed by humic acid. Cobalt sorption isotherms for whole soils at low site coverage were essentially linear and the gradients of isotherms increased with pH. A comparison of isotherm gradients for whole soils and individual soil components supported the suggestion that Co sorption in whole soils is largely controlled by soil oxide materials.     

Mineral Composition and Weathering of Soils Derived from Xiashu Loess

Mineralogical, physical and chemical analyses of the soils derived from Xiashu loess were carried out. The primary minerals of these soils were found to be mainly composed of light minerals, such as quartz, feldspar and mica, with traces of heavy minerals. Clay minerals, more complicate in composition, were dominated by hydromica, accompanied by smectite, vermiculite, chlorite, kaolinite, 2:1/1:1 randomly interstratified minerals and small amounts of quartz, goethite, lepidocrocite and hematite, Clay minerals were characterized by low crystallinity and fine particle size. In light of the quartz/feldspars ratio of the 0.01-0.05mm silt fraction, and the clay mineral composition, the freeness of iron oxide, and the silica/sesquioxide and silica/alumina ratios in < 0.002mm clay fraction, it is concluded that the weathering intensity of these soils was lower than those of red soil and yellow earth, but higher than that of brown earth, and that the soil allitization, depotassication and hydroxylation of cl     

氧化铁对土粒强胶结作用的矿物学证据

DCB脱铁处理高铁土壤前后用NaOH -超声波分散的四个粒级 (<2 μm、2～ 2 0 μm、2 0～ 2 5 0 μm和 2 5 0～2 0 0 0 μm)的矿物组成变化研究表明 :氧化铁对土壤颗粒有很强的胶结能力 ,它可与高岭石、蒙脱石等粘粒矿物胶结形成非常稳定的大颗粒团聚体 ,这些团聚体即使用NaOH -超声波也很难分散     

贵州碳酸盐岩发育土壤磁学性质及其发生机理

本文对贵州碳酸盐岩发育土壤的磁化率、磁化率频率系数和等温剩磁等磁学参数的系统测定以及磁性矿物研究表明，碳酸盐岩发育土壤磁学性质及其变化特征主要受成土地球化学作用和环境影响，具有十分重要的环境指示意义。本文在采用高梯度磁性分离土壤中氧化铁矿物基础上，综合运用Ｘ射线衍射分析、电子探针分析、透射电镜和穆斯堡尔谱等方法，讨论了碳酸盐岩发育土壤中磁性矿物的形成机理。     

浙江省三种红、紫色砂页岩发育土壤的矿物学研究

本文用Ｘ射线衍射分析,红外光谱分析、透射电镜及Ｘ射线荧光分析对浙江省三种红、紫色砂页岩发育的红砂土、紫砂土和红紫砂土的矿物进行了分析。