水泥固化铬污染土强度及浸出试验研究

为了解决重金属铬污染带来的土壤及地下水污染问题,以沈阳铬渣堆场污染土为研究对象,进行水泥固化重金属铬污染土中Cr(VI)和Cr(Ⅲ)试验研究,测定了水泥掺量、养护龄期、铬不同含量及价态对固化土体的无侧限抗压强度及淋滤特性影响.结果表明,水泥是Cr(VI)和Cr(Ⅲ)污染土的有效固化剂,水泥掺量以20%为宜;Cr(VI)和Cr(Ⅲ)对固化土强度都具有弱化效应,Cr(Ⅲ)弱化效应更明显;SEM图从微观上解释了水泥固化铬污染土强度的变化,该变化与无侧限抗压强度试验结果一致.     

六价铬污染土壤还原稳定修复

以常州某关闭化工厂遗留的铬污染土壤为研究对象,利用还原-稳定固化法对铬污染土壤进行修复,通过不同的单因子试验研究,确定最佳还原剂及优化条件,同时优化稳定固化条件,降低药剂成本。实验结果表明:选用酸化硫酸亚铁为还原剂,石灰为固化剂,联合使用,能够有效降低土壤中六价铬的浓度,其Cr(Ⅵ)去除率达到98%以上;Cr(Ⅵ)、总Cr毒性浸出浓度降低率达98%以上,并满足《危险废物鉴别标准浸出毒性鉴别》(GB 5085.3-2007)中的限值要求。     

熟石灰-矿渣联合修复重金属污染土强度及淋滤特性研究

固化/稳定化修复技术已经成为治理重金属污染土的一种有效且经济的技术.以沈阳矿渣堆场污染土为研究对象,使用熟石灰和高炉矿渣作为混合固化剂,进行固化/稳定化联合修复重金属铬和镉污染土试验研究,测定不同固化剂掺量、不同含水量、不同养护龄期条件下,联合固化污染土的无侧限抗压强度、浸出特性及酸中和能力.结果表明,熟石灰-高炉矿渣联合修复镉和铬污染土壤具有有效性,力学性能主要由固化剂掺量和水含量控制,而重金属铬和镉的浸出主要受pH和固化剂掺量的影响;熟石灰与高炉矿渣质量比1∶4作为混合固化剂掺量20％、含水量为最佳含水率22％时,满足填埋场的废物接受标准和相关环境质量标准要求.     

改性生物炭协同硫酸亚铁修复铬污染土壤

以玉米秸秆为原料，在限氧和高温条件下制备成生物炭，并加入KOH溶液对玉米秸秆生物炭进行碱改性处理，利用FTIR、SEM和TGA等测试技术对材料进行表征，考察材料的理化性质，并通过稳定化实验，研究改性生物炭协同硫酸亚铁对铬污染土壤的修复效果。结果表明，改性后生物炭表面的含氧官能团得到强化，出现明显的孔隙管道结构，呈现蜂窝形状，且具有较强的热稳定性。由稳定化实验结果可知，改性生物炭协同硫酸亚铁对铬污染土壤有良好的稳定化效果。最佳的稳定化修复条件为5%投加比例的KBC和7 d的养护时间。土壤中总Cr和Cr(VI)浸出浓度、Cr(VI)含量分别为0.144 mg/L和0.135 mg/L,22.53 mg/kg,均满足《污水综合排放标准》(GB 8978—1996)中总Cr和Cr(VI)的浸出限值1.5 mg/L和0.5 mg/L以及《土壤环境质量建设用地土壤污染风险管控标准》(GB 36600—2018)中第一类用地筛选值30 mg/kg的限值要求。     

核桃壳生物质负载纳米零价铁对Cr(VI)污染土壤的修复研究

将核桃壳负载纳米零价铁制备核桃壳生物质负载纳米零价铁复合材料(WSP@nZVI),投加到Cr(VI)污染土壤中,通过土壤钝化实验,研究投加量、土水比和时间对Cr(VI)污染土壤的修复效果的影响,并探究可能的修复机理。分析处理前后土壤浸出液Cr(VI)浓度、土壤Cr(VI)含量、土壤总Cr含量以及土壤Cr形态含量的变化。结果表明,在投加量为7.5 mg/g,土水比为1∶10 g/mL,时间为2 d时,修复效果最佳。投加量越大,土水比越小,时间越长,修复效果越明显。其修复机制可能为吸附-还原-沉淀与共沉淀3种机理协同作用。     

石灰粉煤灰固化重金属污染土壤的试验研究

利用火山灰材料特性固化/稳定土壤和污泥中的重金属是一种经济高效的土壤修复技术.粉煤灰具有良好的火山灰活性,加入生石灰后形成土壤固化/稳定剂,毒性特性浸出(TCLP).试验结果表明,它能够有效的固化/稳定铅、三价和六价的铬.抗压强度表明了修复后的土壤具备工程可使用性,而浸出试验结果以及X射线衍射、扫描电镜分析说明了相应的固化/稳定机理.     

铬污染土壤药剂稳定化研究

本文以外源添加重铬酸钾的方式制备模拟铬污染土壤,采用硫酸亚铁和碳酸钙对铬污染土壤进行稳定化研究。试验结果表明:当Fe2+与Cr6+化学计量比为6时,硫酸亚铁对六价铬的还原率达到99.51%;与对照相比,FeSO4可使Cr浸出毒性降低95.94%,硫酸亚铁与碳酸钙联用后Cr浸出毒性降低99.49%～99.86%,且在碳酸钙添加量超过3%时Cr浸出毒性基本保持不变。     

六价铬污染土壤常用修复技术的研究进展

土壤六价铬Cr(VI)污染逐渐严重,对农作物和人类健康产生较大危害。介绍了土壤中六价铬的来源、特性、危害及现行的土壤中六价铬环境质量标准,并逐一阐述了淋洗修复技术、化学还原修复技术、微波辐射修复技术、电动力学修复技术、化学吸附修复技术、联合修复技术等六价铬污染土壤施工常用修复技术的研究进展成果。同时,比较几种修复技术存在的优缺点,并展望当前治理六价铬污染土壤的发展趋势。     

铬盐厂遗留土壤淋洗-还原联合修复

以某铬盐厂搬迁遗留地块为研究对象,采用淋洗、还原稳定联合技术对铬污染土壤进行修复,通过不同的单因子试验研究,确定最佳淋洗剂及优化条件,同时优化后续土壤、废液处理条件,达到特定的修复目标。实验结果表明:选用硫酸为淋洗剂,可以有效去除土壤总Cr,硫酸亚铁-石灰联合使用可以有效去除土壤Cr~(6+),亚硫酸氢钠-生石灰联合使用可以有效去除废液Cr~(6+)、总Cr。     

不同异位修复工艺对高浓度铬渣污染土壤中Cr的去除特性

以我国某铬盐厂的两种不同污染特性铬渣污染土壤（A土和B土）为研究对象,探讨了三种异位修复工艺（淋洗、稳定化、湿法解毒）去除铬渣污染土壤中总Cr和Cr（Ⅵ）的效果,并采用改进BCR顺序提取法分析了不同修复工艺对土壤中各形态Cr的去除效果。实验结果表明,三种异位修复工艺对铬污染土壤中Cr（Ⅵ）的去除效果为湿法解毒 > 稳定化 > 淋洗,湿法解毒工艺对A土、B土中Cr（Ⅵ）的去除率分别高达83.26%、92.94%;对铬污染土壤总铬去除效果最佳的是异位淋洗工艺,异位淋洗工艺对A土、B土总铬消减分别达54.87%、80.16%。异位淋洗工艺实现了对水溶态Cr（Ⅵ）、酸溶态Cr（Ⅵ）的泥水分离,是总铬消减的主要原因;稳定化工艺和湿法解毒工艺降低了土壤pH,促进了水溶态Cr、酸溶态Cr及可还原态Cr向可氧化态Cr的转化,因此土中总Cr并未发生显著消减。高浓度铬渣污染土壤经三种异位修复工艺处理后,A土Cr（Ⅵ）仍然残留736.6 mg·kg^-1,B土Cr（Ⅵ）仍然残留245.47 mg·kg^-1,酸溶态Cr的残留是导致三种工艺修复Cr（Ⅵ）效果受限的主要原因。     

土壤酸化及酸性土壤调理剂应用概述

土壤酸化不仅会加剧土壤营养元素的淋溶和固定、促进有毒元素的释放和活化,而且会影响土壤微生物的生命活动、增加环境压力。概述了我国土壤酸化的现状及原因,针对性地提出了施用石灰类、硼泥类、精制有机肥类等酸性土壤调理剂改良治理土壤酸化的措施。     

土壤污染现状及治理措施

阐述了土壤污染的特征、危害和现状,并从物理修复、化学修复和生物修复三方面简要介绍了土壤修复措施,旨在为土壤修复提供科学依据。     

重金属污染土壤淋洗修复技术研究进展

随着我国工业发展的快速发展,大量重金属排放到环境体系中造成了严重的污染,研究经济高效的方法修复重金属污染土壤成为焦点。淋洗技术因其能够高效、彻底地去除污染土壤中的重金属等优点受到人们关注。本文对土壤淋洗技术的概况作了简述,对目前淋洗剂在重金属污染土壤方面的技术特点、适用范围、作用机制进行了总结,对影响淋洗技术的因素和限制条件进行了分析,同时列举了国外经典的化学淋洗修复工程的案例,以期为今后研究提供参考。     

The Impact of PAHs Contamination on the Physicochemical Properties and Microbiological Activity of Industrial Soils

The aim of this article is the study of the potential relationships between PAHs contamination, physicochemical parameters, and microbial activity in industrial soils. The research was based on two series of measurements. The first was conducted in June 2013 and the second in November 2013. Samples used in study were collected from the area of fuel handling and a loading station, located in the Silesia region of Poland. All collected samples were characterized by the following analytical procedures: PAHs content analysis, the basic physical and chemical parameters determinations (pH, CEC, humic acids content, TC, TN, TP) and microbial activity analysis. The obtained results were also subjected to statistical analysis, based on the Pearson's correlation coefficient calculations.

Results collected during described above procedure show that: the PAHs content was highly positively correlated with C and N contents (p < 0.001) and moderately correlated with humic acids and P contents (p < 0.01). This phenomenon confirms the thesis that the increase of soil organic matter content promotes accumulation of hydrophobic organic compounds such as PAHs. Microbiological analysis shows that bacteria from the mesophilic group are most resistant to PAHs contamination. This information indicates that the organisms belonging to this group should be considered as potentially useful in the soil bioremediation processes.     

磷的农业化学(Ⅱ)

作物生长需要的养分,主要是依靠土壤和肥料两种来源供给。在中等产量水平时,作物吸收的氮有３０％～６０％,磷有５０％～７０％,钾有４０％～６０％是靠土壤肥力提供。除极少数无土栽培和根外施肥外,化肥主要是通过土壤向作物提供养分,因此,土壤的物理化学性质对施肥效果特别重要。土壤学是介于地球科学与生命科学之间的一门独立的自然学科。本文从化肥生产者应具备的土壤基础知识出发,只撷取了其中的土壤物理（土壤三相、颗粒、质地、孔隙、水分、空气、温度）,土壤化学（土壤矿物、有机质、胶体、酸碱性）,土壤分类和土壤养分四部分作一简明扼要的介绍。     

Spatial analysis of methane emissions from paddy soils in China and the potential for emissions reduction

China is a major source of anthropogenic methane (CH₄) emissions because it is the world's largest producer of rice grain, nearly all of which is grown in irrigated paddies. This study sought to reduce the uncertainty in estimates of CH₄ emissions from rice cultivation in China by improving the quantification of the effects of management practices (intermittent drainage and fertilizer inputs) on emissions. These results were spatially extrapolated with digital maps of type of rice using new estimates of organic matter and fertilizer inputs, as well as estimates of soil drainage. The estimated total annual CH₄ emissions from rice agriculture in China in 1990 were 9.9 ± 3.0 × 10¹² g. If intermittent drainage practices were adopted on 33% of the poorly drained soils used for rice cultivation in southern China, the estimated emissions would be 8.9 ± 2.7 × 10¹² g CH₄ yr^-1. Reducing projected organic matter inputs by 50% as a sensitivity analysis to reflect the trend for reduced use of organic fertilizer, resulted in emissions of 9.6 ± 2.9 × 10¹² g CH₄ yr^-1, with 8.7 ± 6 × 10¹² yr^-1 emitted with 33% adoption of intermittent drainage on poorly drained paddies. Although intermittent drainage has been shown to reduce emissions by 50%, the area of rice that is relatively easy to drain and re-flood is not very large. The use of intermittent drainage with better drained paddies is limited because of problems with re-flooding and it is also limited with very poorly drained paddies that are difficult to drain. The 10% emission reduction predicted with 33% adoption of intermittent drainage practices, while not large, is conservative and may be possible to realize. These CH₄ emissions results are relative estimates because the uncertainty remains large due to a lack of emissions measurements from paddies in more regions and a lack of detailed information about organic fertilizer application rates. This revised version was published online in August 2006 with corrections to the Cover Date.     

城市土地利用中的土壤污染问题及修复技术探讨

城市土壤对城市生态与环境的可持续发展有着重要意义。因此,因城市土地利用而引起土壤污染问题已经引起人们的高度重视。本文总结并阐述了城市土壤污染的主要来源及类型,并对近年来国内外广泛采用的相关修复技术进行比较、分析,以期为改善城市生态环境质量提供重要的科学依据。     

溶剂萃取法修复石油污染土壤

对溶剂萃取法修复石油类污染土壤的新技术做了较为全面的概述.首先,介绍了溶剂萃取技术的概念、机理和适用范围;其次,介绍了包括有机溶剂、表面活性剂、环糊精、超临界流体在内的萃取剂的研究进展;再次,阐述了影响溶剂萃取效率的因素和溶剂萃取的工艺条件;最后,对溶剂萃取技术的研究和应用做了展望.     

Comparison of P- availability from monocalcium and diammonium phosphates using a mechanistic nutrient uptake model

Calcium and ammonium phosphates are the most commonly used phosphate fertilizers. Since they differ in some chemical aspects it is important to compare their ability for supplying P to plant roots in different soils. The objective of this research was to compare the predicted effectiveness of monocalcium phosphate (MCP) and diammonium phosphate (DAP) for supply of P to maize in 13 soils. Phosphorus was applied at rates varying with soil from 50 to 400 mg kg^–1. Thirty days later P, Ca, pH, and Al were measured in the soil solution and in the solid phase. We calculated buffer power (b) and effective diffusion coefficient (D_e) for P, and used them, together with solution P (C_li), in the Barber-Cushman mechanistic nutrient model to predict P uptake. Monocalcium phosphate and DAP were similarly effective in supplying P to plant roots. Predicted P uptake differed between fertilizers in only three soils, and maximum differences between fertilizers in C_li or resin-exchangeable P (C_si) in any one soil were always less than 30%. The determinations most highly correlated with predicted P uptake were D_e (r = 0.93^**) and C_li (r = 0.60^*). Resin-exchangeable P was not significantly correlated with C_li, D_e, b or P uptake. Calcium, Al, and pH varied with source of P and soil: soils treated with DAP had lower extractable Al, lower Al in solution, and higher soil pH than soils where MCP was applied. Monocalcium phosphate increased extractable Ca whereas DAP did not affect it.Contribution of Purdue Univ. Agric. Exp. Stn. Purdue Journal Paper No. 12094. Received 0000.     

基于细微观结构的煤矸石固土材料固土机理研究

利用XRD、MAS-NMR和SEM分析了煤矸石质固土材料固化土的水化产物以及微观形貌,探讨了煤矸石质固土材料的固土机理,结果表明:(1)煤矸石质固土材料在固化土中的水化产物为纤维状,主要成份为CSH、钙矾石以及少量无定形水合铝硅酸盐,并且随着龄期的增长,水化产物逐渐增多,固化土强度增加.(2)煤矸石质固土材料的固土机理包括三个方面:煤矸石质固土材料自身的水化凝结、离子交换作用以及土壤中活性成分的固结反应,其中煤矸石质固土材料自身的水化凝结是固化土强度增加的主要原因.