腐殖酸对蒙脱石吸附镉离子的影响机理研究

实验研究了腐殖酸存在下重金属元素镉(Cd2 )在蒙脱石表面的吸附过程,对比研究了两种不同腐殖酸对吸附机理的影响。结果表明,重金属离子在蒙脱石表面的吸附作用受介质pH的影响。加入腐殖酸后吸附产生滞后现象,蒙脱石先吸附腐殖酸,之后转变为腐殖酸和蒙脱石共同吸附Cd2 作用,吸附量较单独吸附过程更大。吸附机理与腐殖酸的投加量和投加方式有关。     

The Effect of Humic Acid Adsorption on the Coagulation Stability of Soil Suspensions

Eurasian Soil Science - Humic acid adsorption and its effect on the coagulation stability of soil suspensions were studied. The humic acid (Aldrich Chemie) adsorption from its dilute aqueous...     

腐殖酸对农田土壤磷素吸附行为的影响研究

土壤有机腐殖酸类物质具有巨大的比表面积和表面活化基团,在土壤污染物和养分的吸附、利用和转化过程中起着重要作用。该研究选取5种中国典型农区土壤,采用增加和减少有机腐殖酸类物质含量的方法,设置不同含量梯度,利用振荡平衡法来定量研究不同腐殖酸含量对磷素吸附特性的影响,并对其利用Freundlich、Langumuir和Temkin方程来进行定量化拟合分析研究,试图定量探讨有机腐殖酸类物质对磷素吸附行为的影响。研究结果表明:Freundlich、Langumuir和Temkin这3种方程均可对磷素吸附特征进行拟合,但拟合相关性以Freundlich最好,对于不同土壤而言,对磷素吸附拟合方程的适应性,以Freundlich方程对黑土和红土最好,塿土和黑垆土次之,潮土最差。加入腐殖酸明显地减少土壤对磷素的吸附量和吸附速率。腐殖酸对于土壤磷素有一定的活化激发作用,无论是增加还是减少腐殖酸时,黑土和红土对磷素的最大吸附量变化比例不是很大,而塿土和黑垆土变化最大,可以减少50%～60%左右,而潮土次之。腐殖酸可作为土壤P素增效剂,改善肥料物理性状,提高其稳定性和有效性,尤其是在黄土高原石灰性土更为有效。     

Influence of Humic Acid on Water Adsorption Characteristics of Kaolin and Quartz

Water vapor adsorption isotherms were measured for samples of kaolin and quartz amended with different amounts of humic acid extracted from a Cambic Arenosol under forest. Applying the approximation of the adsorption isotherms with the BET equation the monolayer capacities (surface areas) for the studied systems were calculated. For kaolin systems the surface area decreased sharply at low humic acid additions and this slowly increased with the further rise of the humic acid content, whereas for the quartz the increase of surface area was only noted for high humic acid contents. Using an exponential isotherm equation with a local BET model, the adsorption energy distribution functions were calculated for kaolin systems. The shape of the adsorption energy distributions showed that the increase in humic acid content changed the character of the surface from more hydrophilic to more hydrophobic. For intermediate humic acid contents, the energy distribution function had two maxima – more polar and less polar. At high humic acid contents the energy distribution function tended to the estimated value for pure humic acid, indicating high surface coverage with organic material. As measured by the mercury intrusion porosimetry, for the kaolin samples the amount of the largest pores decreases and the amount of the smallest pores increases with the accumulation of humic acid. For the quartz systems only very high doses of humic acid are reflected in changes of pore size distribution.     

腐殖酸在黑云母表面的吸附动态和分布特征研究

采用原位原子力显微镜智能模式初步观察了弱酸性土壤腐殖酸分子在层状硅酸盐含钾矿物黑云母表面的吸附动态和形貌变化。采用纯化、干燥后的腐殖酸固体样品配制p H 6.0,浓度分别为0 mg L-1、100 mg L-1和1000 mg L-1的腐殖酸溶液。原位观察所用的矿物薄片为土壤中常见的2∶1型含钾矿物—黑云母,其化学结构式为K(Mg2.46Fe0.45Ti0.09)[Al Si3O10](OH)2。结果表明,时间尺度是影响界面上腐殖酸形貌结构的一个重要因素。在通入p H 6.0的腐殖酸溶液作用下,原位反应0~180min内,腐殖酸分子与黑云母(001)面的相互作用以吸附为主并伴随脱附现象,吸附的腐殖酸呈球状,为单个或多个腐殖酸分子的聚集体,高度介于1~5 nm之间;原位反应180~300 min内,黑云母(001)面上吸附的腐殖酸仍以颗粒态为主,高度介于3~5 nm之间,平均为4 nm;而黑云母(001)面上的台阶和边缘位置则分布有较多的片状结构以及黑云母线型边缘诱导产生的链状结构腐殖酸聚集体,其高度介于6~8 nm,较颗粒态腐殖酸的聚集体平均高出约2.5 nm。此外,腐殖酸分子不仅能够在黑云母表面进行吸附和脱附作用,还能够溶解黑云母的表面结构,促进层间K及结构单元内Al和Si的释放。因此,腐殖酸与云母类矿物的界面反应是一个溶解—吸附—聚集并伴随着脱附和离子释放的过程。     

不同处理褐煤腐殖酸对磷吸附特性的研究

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。     

Effects of Clay Surfaces on the Adsorption and Biological Decomposition of Proteinaceous Components of Fulvic Acid

Shaking of an aqueous fulvic acid (FA) solution with montmorillonite at pH 2.5 at room temperature, removed about 43 % of the FA fraction containing proteinaceous components. About 65 % of this fraction was adsorbed reversibly in interlayers, 20 % on external surfaces and 15 % was adsorbed irreversibly. The relative molar distribution of the amino acids (after hot acid hydrolysis) in the original FA, the FA fraction adsorbed in clay interlayers and in the FA fraction not adsorbed by montmorillonite was relatively uniform, indicating that clay interlayers were relatively inefficient for separating proteinaceous constituents from main structural FA components. External clay surfaces, however, appeared to adsorb peptides and/or proteins that differed qualitatively from those adsorbed on internal clay surfaces. Five successive treatments with fresh clay showed that only 61 % of the FA fraction containing proteinaceous components could be adsorbed. The original FA and all fractions separated from it by montmorillonite were able to support microbial growth without the addition of an external N source. The rate of biodegradation decreased when the FA was complexed with montmorillonite.     

Simplified Fixed Bed Design Models for the Adsorption of Acid Dyes on Novel Pine Cone Derived Activated Carbon

A novel activated carbon has been prepared by the activation of ground pine cones using phosphoric acid activation, and the nitrogen Brunauer?CEmmett?CTeller surface area was 869 m² g^?1. Equilibrium isotherms were performed to assess the capacity of the activated carbon using two acidic dyes, namely Acid Blue 113 and Acid Black 1. The monolayer equilibrium isotherm capacities of Acid Blue 113 and Acid Black 1 were 286 and 458 mg dye/g C, respectively. These capacities are significantly higher than commercial carbons and other literature carbons. For the first time, these carbons were tested in fixed bed experimental systems and data analysed using the bed depth service time model (BDST) and the carbon usage rate (CUR) model. In the fixed bed studies, the key parameters for a 20-cm bed depth for the BDST model at 50% breakthrough capacity are (a) for Acid Black, the BDST capacity is 149 mg dye/g carbon and operating time is 1,530 min and (b) for Acid Blue, the breakthrough capacity is 9 mg of dye/g of carbon and operating time is 195 min. The fixed bed study indicates that the BDST design models can be applied satisfactorily, and the pine cone carbon has significant potential but a more mesoporous pine cone carbon is preferable for the larger Acid Black dye. The CUR design method was not successful.     

煤基腐殖酸对土壤砷赋存形态和小白菜生长及砷吸收分布的影响

为探讨部分煤基腐殖酸性质与土壤砷有效性的关系及其在砷污染土壤修复改良中的潜在利用性和应用方向,通过小白菜盆栽试验研究了4种煤基腐殖酸对土壤砷形态和含量及小白菜生长和砷吸收分布的影响。结果表明:6号和10号煤基腐殖酸显著降低了土壤可交换态和碳酸盐结合态砷含量,从而显著降低土壤有效砷含量,抑制砷向小白菜地上部转移和积累;特别是添加10号煤基腐殖酸土壤可交换态砷含量、有效砷含量和小白菜地上部砷总量分别比As处理降低了49.18%,42.22%和15.17%。而9号和11号煤基腐殖酸增加了土壤可交换态和碳酸盐结合态砷含量,显著增加土壤有效砷含量,对小白菜吸收砷并向地上部转移也有一定促进作用,二者土壤可交换态砷含量、有效砷含量和小白菜地上部砷总量分别比As处理增加了10.58%和5.95%,31.11%和22.22%,20.81%和17.21%。4种煤基腐殖酸对小白菜生长均有一定的促进作用,总体表现为10号6号11号9号。因此,E4/E6值小、分子量大、总酸性基含量较低的6号和10号煤基腐殖酸对土壤砷具有明显的钝化作用,可用于轻度砷污染土壤治理中抑制作物对砷的吸收和向地上部转移,实现作物安全生产;而E4/E6值大、分子量小、总酸性基含量较高的9号和11号煤基腐殖酸对土壤砷具有一定的活化作用,在中度和重度砷污染土壤的植物修复中可作为活化剂强化修复速度和效果。     

纳米粘土矿物对阿特拉津的吸附-解吸特性研究

采用批量平衡实验,研究了纳米粘土矿物与原粘土矿物对除草剂阿特拉津的吸附解吸特陛。结果表明,粘土矿物对阿特拉津的吸附-解吸均能用Freundlich方程很好地拟合。随着溶液中阿特拉津浓度的增加,粘土矿物对阿特拉津的吸附量增加;粘土矿物粒径越小,吸附量越大,纳米粘土矿物的吸附量显著大于原粘土矿物。粘土矿物对阿特拉津吸附量大小顺序为：纳米SiO2）纳米蒙脱石〉凹凸棒石〉蒙脱石〉SiO2。粘土矿物对阿特拉津的解吸表现出一定的滞后效应,即粘土矿物吸附的阿特拉津越多,解吸的越少。粘土矿物对阿特拉津的解吸率大小顺序为：SiO2〉凹凸棒石〉纳米蒙脱石〉纳米SiO2〉蒙脱石。     

诺氟沙星在胡敏酸上的吸附热力学与动力学特征研究

根据OECD Guideline106批平衡实验,研究了诺氟沙星在胡敏酸上的吸附热力学和动力学,并探讨了其可能吸附机理。结果表明,诺氟沙星在经过约12h的快速吸附阶段后,进入缓慢吸附阶段,其吸附平衡时间为48h。伪二级动力学方程能够较好地描述不同pH条件下诺氟沙星在胡敏酸上的吸附动力学特性。诺氟沙星在胡敏酸上的吸附等温线符合Freundlich方程,该方程的拟合系数1/n〈0.5,表明诺氟沙星在胡敏酸上为非线性吸附。ΔH0=-48.85kJ·mol-1和ΔG0〈0,表明诺氟沙星在胡敏酸上的吸附是自发进行的放热过程,且离子交换是其主要吸附机理,同时也可能存在着偶极间作用力、氢键力和电荷转移等吸附机理;ΔS0〈0表明吸附过程中熵在减小。吸附位点的能量随着吸附量的增大而降低,也表明胡敏酸的异质性和吸附的非线性。     

腐植酸在土壤中迁移的模拟实验研究

浅层地下水中的腐植酸与人体健康密切相关,腐植酸在土壤中的迁移影响土壤和地下水中腐植酸含量。采用土柱模拟实验,研究了不同条件下腐植酸的迁移规律。结果表明,腐植酸的出水浓度随时间逐渐升高,最后趋于稳定;同一时间段内,初始浓度为15mg·L-1时的出水浓度比10mg·L-1时高,且早24h达到稳定浓度;淋滤液pH为9时的出水浓度比pH为4时高,且早16h达到稳定浓度;粉质粘土柱对腐植酸的吸附和阻滞作用大于砂壤土柱,出水浓度较低,晚32h达到稳定浓度;土层厚为5cm的土柱出水浓度高于15cm土柱,早32h达到稳定浓度。分析认为,土壤对腐植酸的吸附作用是出水浓度变化的主要原因,腐植酸和土壤的理化性质是影响腐植酸在土壤中迁移的主要因素。     

不同腐殖酸类对黄土坡面侵蚀和养分流失的影响

在陕西省长武县黄土高原农业生态试验站进行了在相同的上方来水量18L/min条件下3种不同腐殖酸类(NHA、BFA、FA)的黄土坡面侵蚀和养分流失的试验,分析了不同腐殖酸类及不同量的同一腐殖酸对土壤侵蚀和养分流失的影响。结果表明:不同量的NHA处理下,径流量均随时间的增加而增加,NHA浓度150,300g/m~2的坡面径流量是500g/m~2的坡面径流量的1.14,1.08倍,含沙率和Br-浓度均随时间的增加而减少,累积径流量、累积泥沙量、累积流失量均随用量的增加而减少,150,300g/m~2的坡面累积泥沙量是用量500g/m~2的2.16,1.87倍,累积Br-流失量是用量500g/m~2的1.38,1.23倍,用量500g/m~2 NHA对防止土壤侵蚀和养分流失的效果最佳;不同浓度FA处理下,径流量随时间的增加而增加,FA浓度为0.1%,0.03%的累积径流量是浓度0.05%的1.19,1.33倍,含沙率和Br-浓度大体随时间的增加而减少,累积径流量、累积泥沙量、累积流失量均随浓度的增加先减少后增加,浓度为0.1%,0.03%的累积泥沙流失量是浓度0.05%的3.03,4.09倍,累积Br-流失总量是0.05%Br-流失总量的1.1,1.26倍,浓度0.5%FA对防止土壤侵蚀和养分流失的效果最佳;不同浓度BFA处理下,径流量随时间的增加而增加,BFA浓度为0.1%,0.05%的坡面累积径流量是浓度0.03%的1.15,1.1倍,含沙率和Br-浓度随时间的增加而减少,累积径流量、累积泥沙量随浓度的增加而增加,累积流失量随浓度的增加先减少后增加,浓度为0.1%,0.05%累积泥沙量是0.03%累积泥沙总量的1.36,0.49倍,Br-流失总量是0.05%Br-流失总量的4.06,3.5倍,浓度0.5%BFA对防止土壤侵蚀和养分流失的效果最佳;综合考虑3种不同腐殖酸类防止坡面侵蚀和养分流失效果为BFAFANHA。     

尿素氮形态转化对腐殖酸的响应

通过模拟试验研究了不同用量腐殖酸对土壤中尿素氮形态转化的影响。结果表明,腐殖酸对尿素态氮形态转化的影响受其施用量的制约。与对照相比,低浓度腐殖酸(<15gkg-1)对尿素水解及以后的氮转化过程抑制作用较小,有时甚至促进了尿素水解;高浓度腐殖酸(15gkg-1和20gkg-1)则能明显的抑制尿素水解,延长尿素态氮在土壤中的停留时间,增加铵态氮含量,减少硝态氮的生成及氮素损失量,大大提高尿素利用效率。由此可见,腐殖酸不仅是一种脲酶抑制剂,还是一种硝化抑制剂。     

Critical Comparison of Humic Acid Test Methods

The colorimetric method and the California Department of Food and Agriculture (CDFA) method of evaluating the humic acid content of five raw humate ores and three humate products were compared to the classical technique of extraction in a dilute base followed by precipitation of humic acid by extract acidification and ash removal by hydrochloric/hydrofluoric acid (HCl/HF) wash. Compared to the classical procedure, the colorimetric and CDFA methods overestimated the humic acid content of the eight samples by 120% and 52%, respectively. Therefore, these procedures do not produce a reliably accurate value for the humic acid contents of humates and products produced using materials extracted from them.     

无机酸处理对褐煤腐殖酸含量及特性的影响

研究了不同浓度的各种无机酸对褐煤中腐殖酸含量、CEC及其光学性质变化规律的影响。试验结果表明:H_3PO_4和HCl处理能在一定程度上提高阳离子交换能力,但对腐殖酸含量及光学性质基本无影响。一定强度的HNO_3能使腐殖酸含量增加25％以上,阳离子交换能力有了很大程度提高,且随硝酸强度的变化过程要明显滞后于腐殖酸含量的变化过程,光学性质发生了很大变化。不同褐煤达到最佳处理效果的条件也不尽相同。     

腐殖酸肥料对杨树生长及土壤性质的影响

利用活化后褐煤腐殖酸为吸附基质制成缓效肥料(NHA),研究了其对盆栽杨树生长、土壤酶及理化性质的影响.结果表明:施肥对杨树生长具有明显的促进作用,腐殖酸(HA)的施用对杨树根系促进作用明显,同常规施BE(UREA)及腐殖酸混合肥料(HAUM)相比,NHA显著增加了杨树的茎重及树高,氮肥利用率显著提高,达到了53.8%;HA的施用提高了土壤中蔗糖酶、碱性磷酸酶、多酚氧化酶的活性,降低了土壤脲酶活性,对过氧化氢酶活性影响不大;同UREA处理相比,HAUM处理及NHA处理不同程度地增加了土壤有机质、速效磷及饱和持水量,而速效钾、可溶性盐分、pH有所降低,同HAUM处理相比,NHA处理土壤中的速效氮和阳离子代换量有所增加.     

腐植酸共聚物对土壤酶活性的影响

对使用腐植酸共聚物改良后土壤酶活性进行了研究。实验结果表明改良后的土壤蔗糖酶、脲酶、蛋白酶和多酚氧化酶的活性增强。土壤酶活性的提高表明改良后的土壤结构、性能更适宜土壤微生物的繁殖和生长 ,土壤中的微生物量增加。