共查询到20条相似文献，搜索用时 34 毫秒
1.
2.
水溶性有机高分子对红壤磷吸附特征的影响 总被引：7，自引：1，他引：7
本试验采用连续振荡法,初步研究了水溶性有机高分子材料聚乙烯醇、聚丙烯酰胺和聚乙二醇对磷在红壤中吸附过程的影响,并对该过程拟合出方程。结果表明:在聚乙烯醇、聚丙烯酰胺和聚乙二醇作用下土壤磷吸附动力学以幂函数方程为最优方程,且方程参数与单施磷酸二氢钙的处理方程参数有显著差异性。有机高分子能显著提高磷在红壤中的吸附和土壤pH,但材料之间的土壤吸附量无差异显著性,需进一步研究。 相似文献
3.
The objective of this study was to evaluate the relationship between clay mineralogy, specific surface area (SSA) and micromorphology in polygenetic Konza soil series. Physical, chemical and mineralogical analyses were performed on disturbed soil samples, and micromorphological investigations of selected horizons were done on undisturbed soil samples. X-ray diffraction indicated that lower part of each parent materials has more mectite and less clay mica content than that of the upper horizons in each parent material. Greater amounts of smectite can be attributed to transformation product of the clay mica in to smectite, eluviation from upper horizons or originated from parent material. Specific surface area of upper horizons in each parent material tended to increase to lower horizons. Clay content gradually increased from surface (21%) to the lower part (～48%) of the solum. Clay in Bt horizons had strong birefrengent, sharp boundary, and strong orientation pattern. SSA, clay content increase, clay mineralogy and oriented clay features agreed to one another. Therefore, this relationship gives opportunity to make predictions on extend of SSA and related soil processes by looking at one of these features. 相似文献
4.
Grzegorz Jozefaciuk Christian Hoffmann Manfred Renger Bernd Marschner 《植物养料与土壤学杂志》2000,163(6):595-601
Effects of natural or anthropogenic soil acidification and alkalization on chemical or biological properties have been studied extensively while little is known about changes in physicochemical characteristics, such as surface area or adsorption energy. To investigate this, samples of six Polish soils (Inceptisols, Mollisols) and three Korean soils (Alfisols, Ultisols) of different origin and mineral composition were acidified and alkalized with elevated concentrations of hydrochloric acid and sodium hydroxide ranging from 0.001 to 1 mol dm—3. Surface properties of these soils were studied. The surface area and average adsorption energy decreased in general in both treatments. The treatments induced the decrease in amount of high and medium energy centers, however the fraction of low energy centers increased. The behavior of surface properties differed from the above at treatments at highest reagent concentrations, especially for Korean soils, rich in clay and iron oxides. The general pattern of the adsorption energy decrease observed in most of the soils indicates that the overall water binding forces become lower after treatments. In this case the soil water may be more available for plants, despite its amount decreases. 相似文献
5.
亚热带土壤不同矿物组分中铬的吸附 总被引：1，自引：0，他引：1
J. BAVARESCO J. R. FINK M. L. K. RODRIGUES C. GIANELLO V. BARR&#;N J. TORRENT 《土壤圈》2017,27(1):106-111
Safe application of chromium (Cr)-containing organic industrial wastes to soil requires considering the ability of the soil to adsorb Cr.In this study,the maximum Cr adsorption capacity was assessed for the bulk samples and their clay and iron-free clay fractions of four subtropical soils differing in mineralogy.To this end,the samples were supplied with Cr(Ⅲ) nitrate solutions at pH 4.5 or 5.5.The results of Cr(Ⅲ) adsorption fitted to a Freundlich equation and the adsorption capacity was positively correlated with soil organic matter and iron oxide contents.The clay fractions adsorbed more Cr per unit mass than the bulk soils and the iron-free clay fractions.The Cr(Ⅲ) adsorption capacity increased with increasing soil pH due to more charges on adsorbing surfaces.Our results suggest that the soils rich in organic matter and iron oxides and having a pH above 4.5 are suitable for application of Cr(Ⅲ)-loaded industrial wastes. 相似文献
6.
Despite the current global attention on biochar (BC) as a soil amendment, knowledge is limited on how BC impacts the physical properties of coarse-textured soils (sand > 95%), particularly in tropical regions. A two-season field-study was conducted to investigate the effect of rice straw BC (3% w/w) on water retention, gas transport and structure of a sand-textured tropical soil. We sampled 3 months and 15 months after BC application and measured wet- and dry-region soil water retention, air permeability and gas diffusivity at selected matric potentials. At all measured potentials and for both sampling times, soil water retention was significantly higher (20–150%) for the BC treatment due to increased fraction of smaller pores (< 30 µm) at the expense of macropores (< 100 µm). Although there was no consistent effect of BC on air-filled porosity, BC significantly reduced air permeability and gas diffusivity (~20%) at ?30 kPa matric potential. After 15-months, air permeability decreased by ~15% after BC amendment, but analyses of the pore structure revealed a more tortuous and complex soil structure. Thus, application of rice straw BC to similar coarse-textured soils will improve soil-water relations and over time provide better structure for agricultural purposes. 相似文献
7.
黄土丘陵区两种典型灌木群落坡面侵蚀泥沙颗粒组成及养分流失的比较 总被引：4，自引：0，他引：4
在野外模拟降雨条件下,比较研究了黄土丘陵区柠条(Cnragana korshinkii)和狼牙刺(Sophoraviciifolia)径流小区产流产沙、侵蚀泥沙颗粒组成、比表面积(SSA)及养分流失特征.结果表明,两种灌木群落均能显著减小坡面径流泥沙的流失.产流后流失泥沙黏粒、SSA与养分含量随降雨时间总体呈现降低趋势,其中有机质变化显著,全磷变化不显著.受植被盖度影响,泥沙中黏粒与养分含量均表现为柠条群落>狼牙刺群落>对照裸地.侵蚀泥沙具有富集黏粒和富集养分的特征,富集率随群落盖度增大而增大(柠条>狼牙刺>裸地).不同形态养分富集率不同,其中有机质均在2.5以上,全氮平均富集率为2.13,全磷为1.23.富集率随产流时间呈线性递减.流失泥沙养分含量与黏粒(粒径<0.002 mm)含量及SSA达到极显著的正相关.坡面土壤养分主要以黏粒为载体流失.SSA的变化不仅能体现土壤颗粒组成的变化,而且能够反映土壤养分的变化. 相似文献
8.
《Communications in Soil Science and Plant Analysis》2012,43(9-10):1357-1366
Abstract Iron and aluminum oxides are widespread in tropical environments and increase soil's isoelectric point (IP). Anion adsorption modifies the IP and the surface charge of oxidic materials. This study evaluated IP changes on A‐ and B‐horizon samples of two Brazilian Oxisols upon reaction with acetate, citrate, oxalate, phosphate and sulfate (1 mmol L?1; soil–solution 1∶100; pH 5.5; ionic strength 30 mmol L?1 as NaCl). Most anions seemed to be specifically adsorbed, because the IP decreased after the reaction with the ligands. The IP of natural and of the acetate‐, citrate‐, oxalate‐, phosphate‐, and sulfate‐treated samples followed the order: Red Latosol‐A: 2.89,2.86, <2.50, 2.63, 2.79, 2.86; Red Latosol‐B: 5.92, 5.89, 2.79, 3.42, 3.36, 5.84; Red‐yellow Latosol‐A: 2.89, 2.79, <2.50, <2.50, 2.66, 2.89; and Red‐yellow Latosol‐B: 6.38, 6.29, 3.06, 4.36, 3.69, 6.15. The decrease in IP caused by citrate, oxalate, and Phosphate is relevant because this interferes with charge‐dependent soil reactions. 相似文献
9.
综述了近年来可变电荷土壤化学研究的进展,着重总结了可变电荷土壤中的盐吸附、铁铝氧化物对土壤自然酸化的抑制作用和离子强度对离子专性吸附的影响等特殊化学现象及其微观机制的研究进展。用颗粒表面扩散层重叠导致有效电荷数量减小的原理解释了盐吸附现象和铁铝氧化物对土壤自然酸化的抑制作用。阐明了可变电荷土壤和矿物中介质离子强度影响离子专性吸附的机制,用四层吸附模型解释了离子专性吸附随离子强度增大而增加的现象,并根据胶体zeta电位随离子强度改变而变化的趋势进一步证明了离子强度增大使胶体专性吸附面上静电电位的绝对值减小,是离子专性吸附随离子强度增大而增加的主要原因。带电颗粒表面双电层结构和双电层相互作用的深入研究,有助于阐明可变电荷土壤中一些特殊化学现象的微观机理,从而进一步完善土壤化学理论。 相似文献
10.
11.
The specific surface area (SSA) of a soil is crucial for the interface of ions and water molecules with the soil particles. Therefore, many physical and chemical properties of a soil are determined using its total SSA. Measurement of SSA is time-consuming and laborious, and its estimation using pedotransfer functions is therefore preferred. The objectives of this study were to: (1) analyze the pore–solid interface fractal dimension (D) in soils with different textures from thesouthern part of Iran using estimated improved particle-size distribution (PSD) from the soil primary particles, i.e. clay, silt and sand; (2) develop a multivariate pedotransfer function to estimate D based on PSD; and (3) develop a multivariate pedotransfer function to link the values of D to the SSA. As a result, two pedotransfer functions are presented for estimation of D and SSA. To estimate SSA, the value of D is first obtained using the presented pedotransfer function and these estimated D values are then used in another pedotransfer function to estimate SSA. The pedotransfer functions were validated and it is concluded that they are able to predict the values of D and SSA accurately. 相似文献
12.
With the large-scale cultivation of transgenic crops expressing Bacillus thuringiensis (Bt) insecticidal toxin in the world, the problem of environmental safety caused by these Bt crops has received extensive attention. The effects of soil organic matter (SOM) on the adsorption and insecticidal activity of Bt toxin in variable- and constant-charge soils (red and brown soils, respectively) were studied. Organic carbon in the soils was removed using hydrogen peroxide (H_2O_2). After H_2O_2 treatment, the SOM in the red and brown soils decreased by 71.26% and 82.82%, respectively. Mineral composition of the H_2O_2-treated soils showed no significant changes,but soil texture showed a slight change. After SOM removal, the cation exchange capacity (CEC) and pH decreased, while the specific surface area (SSA), point of zero charge (PZC), and zeta potential increased. The adsorption isotherm experiment showed that the Bt toxin adsorption on the natural and H_2O_2-treated soils fitted both the Langmuir model (R~2≥ 0.985 7) and the Freundlich model (R~2≥ 0.984 1), and the amount of toxin adsorbed on the H_2O_2-treated soils was higher than that on the natural soils. There was a high correlation between the maximum adsorption of Bt toxin and the PZC of soils (R~2= 0.935 7); thus, Bt toxin adsorption was not only influenced by SOM content, but also by soil texture, as well as the SSA, CEC, PZC, and zeta potential. The LC_(50) (lethal concentration required to kill 50% of the larvae) values for Bt toxin in the H_2O_2-treated soils were slightly lower than those in the natural soils, suggesting that the environmental risk from Bt toxin may increase if SOM decreases. As the measurement of insecticidal activity using insects is expensive and time consuming, a rapid and convenient in vitro method of enzyme-linked immunosorbent assays is recommended for evaluating Bt toxin degradation in soils in future studies. 相似文献
13.
研究离子交换中的离子特异性效应有助于揭示离子-带电表面相互作用机制。以蒙脱石Cu2+饱和样为研究对象,采用恒流法研究不同浓度碱金属离子Li+、Na+和K+的吸附动力学过程,并建立1︰1型(LiNO3、NaNO3、KNO3)电解质溶液中离子平衡吸附量与体系吸附活化能之间的关系。结果发现:(1)Li+、Na+和K+在蒙脱石-Cu2+表面的吸附过程仅呈现出弱静电力作用下的一级动力学特征,并存在明显的离子特异性效应。(2)离子非经典极化作用与体积效应共同决定了离子在双电层中的位置,从而导致表面电位存在差异;并且表面电位(绝对值)随着电解质浓度降低而增加,表现为Li+>Na+>K+。(3)根据新建立的模型可预测吸附离子在双电层中的位置,进而求出体系的吸附活化能,并发现离子特异性效应产生的根本原因是由活化能决定的,同时本研究表明建立的新模型在固/液界面反应中具有普适性。本研究将对固/液界面反应理论的完善提供新思路。 相似文献
14.
Jean‐Marie Séquaris Gregorio Guisado Maria Magarinos Carlos Moreno Peter Burauel Hans‐Dieter Narres Harry Vereecken 《植物养料与土壤学杂志》2010,173(5):699-705
According to recent conceptual models, the organic carbon (OC) of soils can be divided into OC fractions of increasing stability from labile free OC to resistant OC associated with the soil mineral phase. In this study, we present a method for quantifying two OC fractions based on soil aggregate–size fractionation and the N2 gas–adsorption method. For this purpose, we analyzed soil material of the plow layer of a Haplic Chernozem subjected to different fertilizer treatments (no fertilizer, mineral fertilizer, mineral and organic fertilizer). The total organic‐C concentration (TOC) and the clay content of the different size fractions were determined as well as the specific surface area (SSAmineral) and the sample pore volume after thermal oxidation (OC‐free). The TOC of the different soil‐aggregate fractions was linearly related to SSAmineral. Clay‐associated OC and nonassociated OC fractions of the different soil samples were quantified using two methods based on the OC surface loading at the clay fraction. The application of organic fertilizer increased the amount of nonassociated OC but hardly affected the concentration of clay‐associated OC. This finding agrees with previous studies on C dynamics in soils and indicates a finite capacity of soil materials to sequester OC. Even without any addition of organic fertilizer, the mineral phase of the analyzed soil material appears to be C‐saturated. 相似文献
15.
上舍流域两种林地土壤结构与抗蚀性 总被引：1，自引：0，他引：1
[目的]为了解土壤侵蚀的机理,探究土壤抗蚀性与土地利用类型、土壤结构的关系。[方法]以安徽省岳西县毛尖山乡上舍村典型小流域马尾松林(Pinus massoniana Lamb)和桑树林(Morus alba L)为研究对象,在0—40cm土壤深度范围内,按照10cm间隔分层取样,室内测定土壤孔径、比表面积、崩解指数、不同径别(0.5,0.5~1.0,1.0~2.0和2.0~2.5mm)根系长度特征。[结果]土壤抗蚀性强弱表现为马尾松林大于桑树林。表层0—10cm范围内,桑树林地土壤根系小于马尾松土壤根系,土壤的抗蚀性随着土层深度的增加而减小;桑树林和马尾松林土壤根系主要分布在0—30cm层次内,而且1mm的根系长度由表层向深层递减,土壤平均孔径随着深度的增加而减小,而比表面积随着深度的增加而增大;在0—40cm深度马尾松各层次孔径分布呈分层现象,而桑树林各层次土壤孔径分布差异不大。土壤孔隙度和土壤孔径越大,土壤抗蚀性越强,而土壤颗粒比表面积越大土壤抗蚀性越小;通过SPSS分析得到桑树林地土壤抗蚀性与土壤根系质量在0.01水平上显著相关,马尾松土壤平均孔径与土壤根系质量在0.05水平上显著相关。[结论]降雨时,由于马尾松林地地表覆盖均匀,坡面产生壤中流下渗,土壤20cm以下分化明显,不易透水,导致下坡壤中流蓄满流出地表带出土壤颗粒。而桑树林地原为耕地无地表覆盖,人为翻种活动频繁,导致土壤层次性质相似,表层土壤颗粒流失严重。 相似文献
16.
Chong Chen Yuji Jiang Bo Sun Hu Zhou Paul D. Hallett 《European Journal of Soil Science》2022,73(2):e13223
17.
利用廉价的农业废弃物稻草秸秆,选择磷酸氢二铵为活化剂在不同的活化温度和预氧化条件下来制备活性炭。应用N2吸附－脱附等温曲线对产品表面孔结构进行表征,采用热重分析来研究稻草秸秆的活化过程。结果表明,同其他处理方法相比,先浸泡后预氧化处理并在700℃下活化制得的样品不但有最大的比表面积（1078．21m^2·g^-1）,其得率和碘吸附值也最大,分别为39．75％和636mg·g^-1热重分析表明磷酸氧二铵的浸泡可以增加稻草秸秆的热稳定性。不论是否经过预氧化,制得的样品平均孔径在2-3nm。（NH4）2HPO4的浸泡可以明显地增加样品的比表面积从而增加其吸附性能。 相似文献
18.
文冠果壳为文冠果榨油后的废弃物,为避免环境污染,充分利用这种废弃物制成高附加值的活性炭,该研究以文冠果壳为原料,采用磷酸活化法制备活性炭,以固液比、磷酸浓度、活化时间和活化温度为自变量,活性炭的碘吸附值为因变量,经响应面试验优化制备工艺,探究文冠果壳活性炭的吸附性能。结果表明,通过响应面试验优化得到最佳工艺条件：固液比1∶1,磷酸浓度71%,活化时间158 min,活化温度540 ℃,此时碘吸附值为（1 127.377±2.406） mg/g,与预测的碘吸附值误差仅为0.390%。与文冠果壳相比,经活化得到的活性炭水分和灰分明显降低,C元素质量分数升高至69.702%;活性炭的比表面积为841.438 m2/g,总孔容为0.593 cm3/g,平均孔径为4.361 nm,孔隙结构发达,主要以介孔为主,且官能团主要为羰基。因此可以用文冠果壳制备出吸附性能好的活性炭,该结果可为磷酸活化法制备文冠果壳基活性炭的工业化生产提供一定参考。 相似文献
19.
Neda Vdovi&#x; Kristina Pikelj Irena Jurina Maja Ivani&#x; Nadia Dunato Antonija &#x;tefan 《植物养料与土壤学杂志》2019,182(2):277-285
Particle size distribution (PSD) is among basic parameters in soil and sediment characterization and provides essential information in sedimentological and environmental studies. The problem with the PSD determination is that for any given sample the result depends not only on the method used but also on the sample pre‐treatment, making them seldom comparable. In this study, the PSD of seven non‐treated and pre‐treated soil samples were determined by four granulometric methods (pipette, sedigraph, particle counter and laser diffraction analysis). Samples were subjected to pre‐treatments commonly used in sample preparation for the PSD determination, i.e., addition of dispersant (sodium metaphosphate) and removal of the organic matter (with hydrogen peroxide). The total organic carbon (TOC) analysis was used to estimate the content of organic matter before and after its removal. The effect of different pre‐treatments was evaluated based on the PSD variations and the changes in the specific surface area (SSA) of the samples. The results highlighted differences in the PSD curves of samples depending on the granulometric method and pre‐treatment applied. The most pronounced difference was the higher amount of clay fraction determined by settling techniques. The role of hydrogen peroxide in disruption of aggregates was evident in the increase in the SSA as well as the share of fine fraction determined by all four techniques, while sodium metaphosphate made no modifications of the SSA but acted in favour of prolonging settling of clay particles and increasing its content obtained by settling techniques. 相似文献
20.
针对食用菌培养基废弃物（菌糠）的资源浪费与环境污染问题,该研究提出以不同出菇次数菌糠为原材料,高温碳化制备系列菌糠基多孔碳,并应用于锂硫电池正极中作为碳骨架材料,探究出菇次数对孔隙结构和电化学储锂性能的影响。结果表明,出菇1次菌糠基多孔碳为蜂窝状网络结构,出菇3次菌糠基多孔碳为小颗粒状;出菇0、1、3次菌糠基多孔碳比表面积分别为 147.54、270.88和258.39 m2/g;出菇 1 次菌糠基多孔碳具有完整导电网络,载硫后相对于出菇0、3次菌糠基,表现出最高的可逆比容量（916.81 mAh/g）和较好的动力学性能。出菇1次菌糠基多孔碳经KOH活化后,获得具有发达三维孔道的海绵状多孔碳（AMRC-Ⅰ）,比表面积增大为1 591.06 m2/g,孔径2～5 nm的介孔比例为88.03%,初始放电比容量为1 111.31 mAh/g,100 次循环后保持355.99 mAh/g的可逆比容量,循环更加稳定。该研究表明出菇次数可以调控菌糠基多孔碳的微观结构,进而影响载硫正极的电化学储锂性能,可为菌糠废弃物的高价值利用提供新思路。 相似文献