共查询到16条相似文献,搜索用时 187 毫秒
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采用吸附等温线的试验方法,研究了平衡溶液中磷浓度、反应时间及介质pH对不同处理的2种褐煤腐殖酸吸附磷的影响及其规律性。结果表明:在试验pH范围内,pH的升高减缓了吸附反应进行的速度,对于未经硝酸处理的样品S1,在pH为4.7时,吸附量和分配系数有一最大值,而样品S2,随着pH的升高,吸附量和分配系数一直减小;经硝酸处理后,样品对磷的吸附能力降低,一定条件下其单位吸附量仅为处理前的5.33%。适宜的固液比例可提高2个不同处理供试样品对磷的单位吸附量,其等温吸附规律可用Langmuir方程来加以描述;其吸附动力学用Elovich方程描述最佳。 相似文献
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长期秸秆还田下土壤铵态氮的吸附解吸特征 总被引:8,自引:0,他引:8
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不同原料生物炭对氮、磷、钾的吸附和解吸特性 总被引:5,自引:2,他引:3
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褐煤腐殖酸对铵的吸附特性研究 总被引:2,自引:0,他引:2
研究了铵浓度、处理时间及介质pH对2种褐煤腐殖酸吸附铵的影响及其规律。结果表明,褐煤腐殖酸对铵的吸附等温式可用Freundlich等温曲线描述,其动力学吸附方程用Elovich方程描述最佳。在pH7.04时,介质pH的升高有利于铵的吸附。当pH4.03时,主要以物理吸附为主;当4.03. 相似文献
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不同来源腐殖酸对铜吸附量和吸附机制的研究 总被引:16,自引:1,他引:16
本研究从三种供试材料:草炭、褐煤和风化煤中提取腐殖酸,采用NH4OAc和EDTA两种解吸剂,研究三种来源腐殖酸对Cu2+的吸附能力和吸附机制。研究结果表明:三种来源腐殖酸对Cu2+的吸附在吸附量上没有明显差异,但吸附机制却并不完全相同。三种来源腐殖酸对Cu2+的吸附均主要通过离子交换和络合(或螯合)作用,其中,草炭和褐煤提取的腐殖酸的离子交换作用显著大于风化煤提取的腐殖酸,而风化煤提取的腐殖酸的络合(或螯合)作用则明显大于草炭和褐煤提取的腐殖酸。 相似文献
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褐煤腐植酸对钾的吸附特性研究 总被引:6,自引:0,他引:6
为给褐煤的有效利用和腐植酸缓效肥的研制提供理论依据,本试验采用吸附等温线的试验方法,探讨了K+平衡溶液浓度、平衡时间、pH值及固液比对褐煤腐植酸钾吸附的影响。结果表明:介质pH值升高有利于腐植酸样品对钾的吸附,且能加快吸附反应的速度;当pH<4.4时,Kd1>Kd2,此时以物理吸附为主。当7.12Kd1<Kd2,化学交换占主导地位。其等温吸附曲线符合Langmuir吸附形式,动力学吸附用Elovich方程描速最佳。经硝酸处理后的褐煤腐植酸样品对钾的吸附能力有了一定程度的提高。适宜的固液比能提高2种样品对钾的单位吸附量,分别在固液比为0.06和0.04时达最大,其单位吸附量分别为0.079 g/g和0.094 g/g。 相似文献
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本文研究了NaCl、Na_2SO_4、Na_3PO_4 3种背景电解质对牛粪生物质炭中腐殖酸吸附和解吸的影响。结果表明:在这3种背景电解质作用下,牛粪生物质炭对腐殖酸的吸附量和吸附率随着加入液腐殖酸浓度的增加而增加,但是增加速度逐渐变缓。3种背景电解质相比,NaCl中牛粪生物质炭对腐殖酸的吸附量和吸附率均为最高,吸附量范围为0.13~6.10 mg/g,吸附率范围为25.40%~87.14%。随着加入液腐殖酸浓度的增加,吸附态腐殖酸的解吸量逐渐增加,解吸率逐渐减小。3种背景电解质相比,Na_2SO_4中牛粪生物质炭吸附的腐殖酸的解吸量最高,解吸量范围为0.15~0.78 mg/g。加入液腐殖酸浓度为140 mg/L,3种背景电解质中牛粪生物质炭吸附的腐殖酸的解吸量均达到最大值,解吸量的大小顺序为Na_2SO_4Na_3PO_4NaCl。Na_3PO_4对腐殖酸的解吸率影响最大,解吸率范围为17.24%~90.55%,NaCl对腐殖酸的解吸率影响最小,解吸率范围为8.22%~53.54%。用Langmuir拟合3种背景电解质中腐殖酸的等温吸附曲线和等温解吸曲线,其相关系数都达到显著水平。研究结果揭示了不同背景电解质对牛粪生物质炭吸附和解吸腐殖酸的影响,可为土壤保土保肥提供理论参考。 相似文献
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白浆土是吉林省和黑龙江省东部地区的主要农田土壤之一,研究白浆土对腐殖酸的吸附作用,可为探究白浆土的固碳潜力提供理论依据。采用批量平衡法,分析不同有机碳含量的白浆土及其组分(包括去有机质土壤、粉粒、黏粒)对腐殖酸的吸附动力学和等温吸附特性。结果表明:随吸附时间的延长,白浆土及其各组分对腐殖酸的吸附量逐渐增加;整个吸附动力学过程可划分为快速(0~30 min)和慢速(30~480 min)反应阶段,伪二级动力学方程的拟合效果优于Elovich、双常数和伪一级动力学方程。白浆土及其各组分对腐殖酸的吸附量随腐殖酸初始浓度的增加逐渐增大,Langmuir方程的拟合效果通常优于Freundlich方程和Temkin方程。随白浆土有机碳含量的增加,其对腐殖酸的最大吸附量分别为26.9,24.1,15.6 mg/g。而白浆土不同组分相比,最大吸附量的顺序依次为黏粒>去有机质土壤>粉粒,黏粒对腐殖酸的吸附量分别是原土的2.15~3.88倍,去有机质土壤的1.61~2.21倍,粉粒土壤的7.90~8.65倍。有机碳含量低的白浆土对腐殖酸具有更强的吸附能力,黏粒含量高的白浆土对腐殖酸的吸附潜力更大。 相似文献
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中低分子量腐殖酸提高冬小麦磷吸收和产量的机理 总被引:2,自引:2,他引:0
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The adsorption of ionic Cd has been investigated on three humic acids isolated from podzol, rendzina and brown Mediterranean soils of Tuscany. The adsorption isotherms have been determined at 5 and 25°C. Cadmium adsorption was described by the Langmuir adsorption equation. Langmuir parameters were related to the functional groups content of humic acids and decreased in the following order: rendzina>brown Mediterranean soil>podzol. Adsorption was independent on temperature and increased with pH. Desorption experiments with 0.1 N NH4OAc and 0.25 M Cu (OAc)2 proved that Cd is adsorbed on humic acid about 50% in an exchangeable form and 50% in coordination complexes. 相似文献
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Measurement of electrostatic and site-specific associations of alkali metal cations with humic acid 总被引:1,自引:0,他引:1
A discontinuous acidimetric titration method incorporating ultrafiltration was developed to measure the association of a soil humic acid with Li+ t, Na+ and K+ (pH 3 to 8). In addition, possible site-specific binding of these alkali metal cations was investigated using desorption experiments at pH 1. Li, Na and K cations behaved equivalently in the titrations and the amounts of these cations associated with the humic acid was measurable at all pH values between 3 and 8. Up to 90% of the total alkali metal cation was humate-associated at pH 8. The absolute amount of humic-associated cation did not depend on the alkali metal cation concentration, but rather on the solution alkalinity. In addition, the net charge of the humate polyanion made a negligible contribution to the electroneutrality of the bulk solution under all conditions. These results are consistent with a diffuse layer model of hydrated humic acid in which the alkali metal cations neutralize the humic charge. The association of Na+ andK+ with humic acid at pH 1 was successfully described by a Langmuir adsorption model. The number of sites per g of humic acid was very small, and greater for K+ than for Nat. Lithium cations exhibited no detectable humic association at pH 1. These differences suggest that humic acids may have a small number of specific binding sites for which the size of the hydrated cation is important. 相似文献
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Natthapol Chittamart Janyaluck Inkam Daojarus Ketrot Timtong Darunsontaya 《Communications in Soil Science and Plant Analysis》2016,47(20):2348-2363
Zinc (Zn) is a vital plant nutrient that is widely deficient in Thai cultivated calcareous soils. The chemical fractionation and adsorption of Zn are among the most important solid- and liquid-phase interactions that determine the retention of Zn in the soils. This study aimed to investigate the fractionation and adsorption isotherms of Zn in cultivated Thai calcareous soils. The results of sequential extractions showed that Zn is mainly distributed in residual fractions followed by organic-bound, iron and manganese oxides-bound, carbonate-bound, and exchangeable Zn, respectively. Zinc adsorption was well fitted by the Langmuir and Freundlich isotherms. Thai calcareous soils had high Zn adsorption capacity. Soil pH, organic carbon, calcium carbonate, cation exchange capacity, and extractable calcium were the major soil properties that affected the Zn adsorption isotherms in these soils. Zinc hydroxide was the solid precipitate and the Zn hydroxide ion (ZnOH+) was the dominant Zn ion in alkaline equilibrium solution. 相似文献
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胡敏酸对铵钾在粘土矿物上交互作用的影响 总被引:1,自引:0,他引:1
ZHANG Wen-Zhao CHEN Xiao-Qin ZHOU Jian-Min LIU Dai-Huan WANG Huo-Yan DU Chang-Wen 《土壤圈》2013,23(4):493-502
Interaction of ammonium (NH+4) and potassium (K+) is typical in field soils. However, the effects of organic matter on interaction of NH+4 and K+have not been thoroughly investigated. In this study, we examined the changes in major physicochemical properties of three clay minerals (kaolinite, illite, and montmorillonite) after humic acid (HA) coating and evaluated the influences of these changes on the interaction of NH+4 and K+on clay minerals using batch experiments. After HA coating, the cation exchange capacity (CEC) and specific surface area (SSA) of montmorillonite decreased significantly, while little decrease in CEC and SSA occurred in illite and only a slight increase in CEC was found in kaolinite. Humic acid coating significantly increased cation adsorption and preference for NH+4, and this effect was more obvious on clay minerals with a lower CEC. Results of Fourier transform infrared spectrometry analysis showed that HA coating promoted the formation of H-bonds between the adsorbed NH+4 and the organo-mineral complexes. HA coating increased cation fixation capacity on montmorillonite and kaolinite, but the opposite occurred on illite. In addition, HA coating increased the competitiveness of NH+4 on fixation sites. These results showed that HA coating affected both the nature of clay mineral surfaces and the reactions of NH+4 and K+with clay minerals, which might influence the availability of nutrient cations to plants in field soils amended with organic matter. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(6):683-698
Boron (B) adsorption increased with increasing concentration. Langmuir adsorption isotherm was curvilinear. The maximum value of adsorption maxima (b1) was observed Sagipora soil and maximum bonding energy (k) constant was in Anantnag soil. The Langmuir isotherm best explains the adsorption trend at low adsorbent concentrations. A significant correlation among b1, clay, and cation exchange capacity was observed. Linear affiliation was observed in all the soils at all concentration, indicating that B adsorption data conform to the Freundlich equation. Soils with greater affinity for B adsorption, like Sagipora, tended to desorb less B. Boron desorption was positively and significantly correlated with sand content and negatively with clay content and cation exchange capacity. The maximum value of 50.76 mg g?1 for desorption maxima (Dm) was observed in Sagipora soil, and mobility constant (Kd) was maximum in Khag soil (0.412 ml kg?1). 相似文献
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B. I. Olu-Owolabi D. B. Popoola E. I. Unuabonah 《Water, air, and soil pollution》2010,211(1-4):459-474
Pre-modification of bentonite clay with goethite, humic acid, and a binary mixture of goethite and humic acid reagents increased its cation exchange capacity from 95 to 105.32, 120.4, and 125.8 meq/100 g of bentonite clay, respectively. The effective pre-modification of bentonite clay with goethite, humic acid, and goethite–humic acid reagents was confirmed from their Fourier transform infrared spectra which suggested that modification was effective on the AlAlOH and Si–O sites for goethite and humic acid modification and AlAlOH for goethite–humic acid modification. The presence of 0.001 M NaNO3 electrolyte increased the adsorption capacity of bentonite clay. Temperature was observed to favor the adsorption of Cu2+ and Cd2+ onto both the raw and modified bentonite clay samples. The goethite–humic acid-modified bentonite gave the best adsorption capacity of ≈10 and 16 mg/g at 30 and 50°C, respectively, for both metal ions. The inner sphere complexation mechanism was suggested for the adsorption of both metal ions onto the modified adsorbents. Modifying bentonite clay with a binary mixture of goethite and humic acid reduced the selectivity of bentonite clay for either Cu2+ or Cd2+. Preadsorbed goethite and humic acid on bentonite clay will further reduce the mobility of heavy metal ions in soils and in aquatic environments. 相似文献