共查询到20条相似文献，搜索用时 968 毫秒
1.
采用30 W石英紫外灯作为光源,研究了乐果在二氧化钛悬浮体系中光催化降解反应的动力学规律。考察了乐果起始浓度、TiO2用量、溶液pH值及温度对乐果光催化降解速率的影响,结果表明,乐果光催化降解符合表观零级动力学规律。由于速率常数k与乐果起始浓度有关,表明乐果光催化降解反应不是一个简单的零级反应。 相似文献
2.
膨润土提纯后的尾矿主要含石英、斜绿泥石和白云母等矿物,以尾矿为主原料制备了复合陶瓷颗粒,采用XRD,IR和SEM探讨了烧结工艺对结构变化的影响,研究了复合陶瓷颗粒的组分变化、烧结温度、pH、初始浓度、吸附时间和温度对Cr(Ⅵ)离子吸附效果的影响,探讨了动力学和热力学变化。结果表明,烧结温度对吸附影响不大,烧结适宜温度为1000℃,陶瓷颗粒的主晶相为石英和硅灰石,表面为不均匀多孔结构。吸附的最佳吸附条件是pH值1、陶瓷颗粒用量1 g、吸附时间12 h及铬离子初始浓度100 mg/L,吸附率达96.33%。吸附行为符合准二级动力学方程,属于单分子层化学吸附;热力学数据说明,吸附反应为自发吸热反应。 相似文献
3.
黑曲霉菌浸出蛇纹石尾矿中钴和镍的实验研究 总被引：1，自引：0，他引：1
利用黑曲霉茵浸出蛇纹石尾矿中钴和镍的实验显示出明显的浸出效果,实验中将黑曲霉菌加入含有蛇纹石尾矿粉体的培养液5 d后,对培养液中pH值以及Mg,Co,Ni等的含量变化分别进行测试:pH由7.60降到4.20后,SEM分析得出有茵体-矿物复合体形成;Mg浓度是未加细菌的浸出液中的2.25倍,Co浓度是未加细茵的浸出液中的3.39倍,Ni的浓度是未加细菌的浸出液中的2.38倍;FTIR分析得出600 cm-1,1 100cm-1,3 690 cm-13处谱峰明显下降,反映了还有镁等金属元素的浸出.此实验证实该方法可以作为对于蛇纹石尾矿中金属元素的再利用一种有效手段,进而也达到对金属元素污染的治理. 相似文献
4.
黏土质白云岩是新生代形成的弱固结沉积白云岩,具有丰富且开放的孔隙率及高化学反应活性,其作为环境工程材料的应用值得探讨。本文研究了黏土质白云岩去除溶液中铅的效果和作用机理,考察了黏土质白云岩除铅动力学以及初始浓度、固液比对除铅效果的影响。结果表明,黏土质白云岩与不同浓度的铅溶液反应达到平衡所需的时间不同,初始铅浓度越高反应平衡时间越长,与铅浓度100 mg/L溶液反应70 h才基本达到平衡;黏土质白云岩除铅效果主要受反应平衡后溶液的p H值控制,固液比也可影响溶液p H值;固液比越高,平衡p H值越高,铅去除越完全;黏土质白云岩去除溶液中铅离子的作用机制是其中的白云石诱导的铅沉淀,白云石溶解同时形成了碱式碳酸铅。 相似文献
5.
金,铀,硅溶解性状的实验研究 总被引：5，自引：0，他引：5
在ＰＨ２Ｏ为１５０ＭＰａ，ｐＨ为１０的Ｎａ２ＣＯ３溶液中混合花岗岩的金、铀、硅溶解实验表明，温度３５０—４００℃时有利于金的溶解，２００—３００℃时有利于铀溶解，而硅的溶解随温度的增加呈线性增长。在ＰＨ２Ｏ为１５０ＭＰａ，３５０℃状态下，铀、硅的溶解随Ｎａ２ＣＯ３浓度的增加而增加。当用ＨＣｌ调节Ｎａ２ＣＯ３溶液的ｐＨ值时，金偏向溶于碱性介质，铀偏向溶于酸性介质。在ＰＨ２Ｏ为１５０ＭＰ。，３５０℃不同的碱性溶液中，金与硫化物、氯化物，铀与碳酸盐或碳酸盐－硫化物关系密切，表现金的亲硫性和铀的亲氧性。“焙烧”实验表明，构造、岩浆活动等热事件对金、铀、硅溶解起促进作用。 相似文献
6.
有机酸对长石溶解度影响的热力学研究 总被引：16，自引：0，他引：16
为明确认识有机酸（草酸、醋酸）对长石溶解度及储层次生孔隙发育的影响，本文利用热力学方法，计算了不同温度、酸度下钾长石在含有醋酸根0.05mol/L、草酸0.0055mol/L的溶液中的溶解度及草酸和醋酸对溶液酸度的影响，计算的结果表明醒酸根与铝的络合作用只发生在偏酸性的溶液体系中，并且随温度升高要求酸度增加，实际的络合能力降低，醋酸根的络合作用对长石溶解度的增加作用极及有限，最高时不足一倍；但醋酸能有效地缓冲溶液酸度，从而提高长石溶解度。草酸根与铝的络合作用发生在弱碱性至酸性条件下，温度升高，络合能力增加，络合效应对长石溶解度，草酸根上铝的络合作用发生在弱碱性至酸性条件下，温度升高，络合能力增加，络合效应对长石溶出量的增加最多可达2个数量级以上，草酸的浓度太低无法通过缓冲溶液在较高的酸度下来促进长石的溶解，草酸和醒酸能否促进储层次生孔隙的发育取决于盆地流体的酸度及组成流体的缓冲体系。 相似文献
7.
通过粉煤灰与水6种不同比例的混合实验,利用质量平衡模型模拟分析混合静置0,1,3,7,14,21d后的水化学组分,以揭示粉煤灰浸出液中水化学组分的形成机制。研究结果表明:灞桥电厂粉煤灰浸出液为高pH值溶液,浸出液pH值急剧上升是粉煤灰中碱性氧化物CaO水解的结果;粉煤灰-水反应系统中,矿物的溶解沉淀作用和阳离子交换作用是主要的水文地球化学作用。 相似文献
8.
利用金袋热设备，于３００℃，５０ＭＰａ和流动条件下（流速：７ｍｌ／ｈ和１ｍｌ／ｈ研究了斜长石与１ｍｏｌ／ｋｇＮａＣｌ溶液的相互作用，还在同一温度压力下进行了静态实验，着重考察反应后溶液化学和长石表面化学成分的变化，以探讨钠交代作用的机理，结果表明，反应反溶液的ＰＨ值升高，Ｎａ含量降低；Ｓｉ，Ｃａ，Ｋ和Ａｌ转入溶液的特征与反应状态以及溶液流速有关；斜长石的钠交代作用涉及及钙长石组分溶解和钠长石组分结 相似文献
9.
磷石膏中的磷在雨水淋滤作用下浸出,将污染堆场附近水体。本研究采用生物炭固化磷石膏中的磷,以减少其对周遭水体的污染。主要通过模拟固化实验和对照浸出实验,分析生物炭用量、反应时间和温度、初始pH值对固化效果的影响,通过XRD、SEM-EDS分析固化后的生成物。实验结果显示,在生物炭用量为25 mg时,单位固化量达到最大值13.20 mg/g;在反应温度T=293 K、初始pH=7条件下,反应平衡时间72 h时浸出液的磷平衡浓度Ce= 1.40 mg/L;温度提升有助于提高生物炭的固化效果,当T=308 K时,浸出液的磷平衡浓度Ce=0.167 mg/L;碱性条件有利于固化反应持续进行,在pH=11条件下,浸出液的磷平衡浓度Ce=0.153 mg/L。实验结果表明生物炭对磷石膏中的磷具有明显的固化效果。磷石膏中的二水硫酸钙溶解后,Ca2+与表面带负电的生物炭结合,在生物炭显微结构的凹陷处,化学吸附溶液中的磷酸根生成了絮状、团簇状的羟基磷灰石(HAP)沉淀,从而使浸出磷得到有效控制。 相似文献
10.
利用菱镁矿尾矿制备纳米级片状氢氧化镁 总被引：1，自引：0，他引：1
为了对菱镁矿尾矿进行综合回收利用,文中对利用菱镁矿尾矿制备纳米级片状氢氧化镁工艺进行了研究。通过对菱镁矿尾矿的煅烧、与硫酸反应制备硫酸镁以及纳米氢氧化镁的制备工艺和性能表征,成功制备了原始粒径为纳米级、颗粒呈片状的氢氧化镁粉体。利用轻烧镁粉制备硫酸镁溶液的工艺是将轻烧镁粉与水配制成浆料,然后与酸进行反应。反应后控制体系的pH值在5~6,然后进行过滤。制备氢氧化镁的工艺条件为:Mg2+初始浓度为22.75g/L,反应温度为50℃,反应时间为5min,原位表面改性剂为钛酸酯偶联剂YB-502,用量为氢氧化镁质量的1.5%。制得的氢氧化镁结晶情况良好,为片状纳米粉体,其片径100nm左右,片厚10nm左右。氢氧化镁的二次颗粒粒径为d50=0.95μm,d97=3.53μm。 相似文献
11.
深层、超深层中有机酸的分布特征及其热稳定性对储层物性有着重要影响。采用高温高压水—岩模拟装置对储层中典型一元和二元有机酸（乙酸和乙二酸）的分解反应进行了模拟,对动力学参数进行了计算,并分析其影响因素。结果显示:乙二酸比乙酸更容易分解,且分解反应的速率更高;乙酸和乙二酸分解反应的起始温度分别为230 ℃和180 ℃,其反应速率随着温度的升高而急剧增加。反应体系中高pH值和钾长石的存在明显提高了乙酸和乙二酸分解反应的反应速率,但对起始温度影响较小。高流体压力和静岩压力均会抑制乙酸和乙二酸的分解,在提高有机酸分解反应起始温度的同时降低分解反应速率。从地质意义上来讲,相对高压、低地温的地层环境更有利于有机酸的保存,因此具有低地温梯度的沉积盆地形成深层—超深层优质储层的可能性更高。 相似文献
12.
E. Hong C. M. Herbert A. M. Yeneneh T. K. Sen 《International Journal of Environmental Science and Technology》2016,13(11):2629-2638
Significant amount of slurry waste is produced from mineral processing plants globally constituting high levels of both kaolin and sand in aqueous suspension. Large quantities of slurry and mine tailings require efficient handling, transportation and storage system. The transportation and treatment of kaolin–sand slurry is dependent on its rheological behaviour which is a function of temperature, total solid concentration and pH. In this study, the effects of total solid concentration, pH and temperature on rheological behaviour of kaolin–sand mixture were investigated. These parameters were varied to analyse the viscosity, yield stress, flow index and shear force requirements of the mixed kaolin–sand suspension as a function of these varying parameters. Experimental rheological investigation conducted on rotational stress-controlled rheometer equipped with Peltier concentric cylinder system showed that the kaolin–sand mixture suspension is shear thickening in nature. The shear stress-rate rheograms for the kaolin–sand suspension can be modelled by the Herschel–Bulkley model with high levels of accuracy for pH range of 4–11, temperature range of 20–50 °C and solid concentration of 5–50 %. Solid concentration of the suspension was found to significantly affect the rheological behaviour of the mixture where higher kaolin–sand slurry concentration resulted in greater viscosity and the trend becoming less predictable for solid concentration greater than 50 % by weight. pH was another factor affecting the rheological behaviour of kaolin–sand slurry. pH of 3 or less resulted in the dramatic increase of viscosity of the suspension possibly due to the isoelectric point of the mixture system found between pH of 3 and 4. 相似文献
13.
Sorption and desorption behavior of lead on a Chinese kaolin 总被引：1，自引：0，他引：1
Shengli Wang Zhongren Nan Xinde Cao Qin Liao Jiao Liu Wenfei Wu Ting Zhou Cuicui Zhao Wangqiang Jin 《Environmental Earth Sciences》2011,63(1):145-149
The sorption and desorption of Pb on kaolin from Suzhou, China were investigated. The sorption experiment was conducted in
a 0.01 M NaNO3 aqueous solution with respect to the effects of initial Pb concentration, pH, solid/solution ratio, and temperature. Langmuir
and Freundlich models well described equilibrium isotherms of Pb sorption. Less than 5% of Pb sorbed was desorbed with 0.01 M
NaNO3 extraction, suggesting a dominant specific sorption of Pb. As the initial pH increased, the sorption of Pb on the kaolin
increased. More than 60% of Pb was sorbed at pH 2.69 far below the point of zero net charge of the kaolin at 4.2, indicating
a mechanism of Pb inner-sphere complex or by chemisorption. Lead sorption decreased with increasing temperature, indicating
a process of exothermic sorption. 相似文献
14.
This study examined the interaction between Cr(VI) and a Fe-rich soil in the presence of low-molecular-weight organic acids
as a function of pH. Oxalic and tartaric acids were chosen since they existed in soils commonly. Batch experiments showed
that adsorption of Cr(VI) by the soil within the pH range examined was inhibited in the presence of oxalic acid, which was
more pronounced when the initial ratio of [oxalic acid]/[Cr(VI)] was raised from 1:1 to 2:1. With the addition of tartaric
acid, concentration of Cr(VI) in equilibrium solutions was far less than that of single adsorbate system across the pH wide
(2.5–5.5), which was noticeable especially at low pH. The results were attributed to Cr(VI) adsorption and, particularly,
the soil surface catalyzed reduction of Cr(VI) to Cr(III) by tartaric acid. The data reported in this paper suggested that
the mobility, the bioavailability, and the toxicity of Cr(VI) in soil environments might be greatly affected by pH, the presence
and nature of low-weight-molecular organic acids (oxalic and tartaric acids). 相似文献
15.
为探讨花岗岩母质红壤吸附水中砷(Ⅴ)的效果和机理, 采用静态吸附实验, 研究溶液砷初始浓度、反应时间、温度、pH值等因素对红壤吸附水中砷的影响.当溶液砷初始浓度小于5.0 mg/L时, 红壤对砷的去除率均大于97%;随着砷初始浓度增大, 去除率逐渐降低; 反应初期(0~120 min), 红壤对砷的去除率迅速增大至95.0%左右.此后, 去除率缓慢增大, 直到720 min后, 去除率达到97.0%左右, 并趋于稳定; 在砷初始浓度一定时, 红壤对砷的吸附量随着温度的升高逐渐增加, 但增加幅度较小; 红壤对砷的去除率随着体系pH值的增大呈减小趋势; 正交试验表明, 在砷初始浓度为5.0 mg·L-1、反应时间为120 min、pH为5.0及反应温度为40℃的组合下, 红壤对砷的去除率最大. 相似文献
16.
为了研究不同酸碱环境下锌离子对饱和高岭土压缩特性影响,以及锌离子向其中扩散特性,利用室内人工配制的重塑土开展了一维固结试验和土柱扩散试验。试验结果表明,锌离子浓度不高于0.05 mol/L时,污染土的压缩指数变化不大,但氢氧化锌沉淀量的增加会导致高岭土的压缩性略有降低。高岭土处于碱性环境时,其上部自由溶液中锌离子浓度降低最快,中性环境次之,酸性环境时最慢。溶液电导率可间接反映出其中的溶解态锌离子浓度,高岭土处于中性和碱性环境时,土柱上部自由溶液的电导率与溶液中锌离子浓度呈正相关,而当高岭土处于酸性环境时,土柱上部自由溶液的电导率与溶液中锌离子浓度呈负相关,对于这种酸碱土体环境下的反常规律,在利用溶液电导率快速评价重金属离子浓度时需引起重视。 相似文献
17.
《矿物学报》2013,(Z1)
A natural colloidal pyrite calcined in N2 atmosphere was utilized to remove Cu(II) from aqueous solutions in present work. Effect of calcination temperature, initial solution pH, reaction time, initial Cu(II) concentration, sorption temperature, foreign ions and the dissolved oxygen (DO) on Cu(II) removal was investigated. The results showed that colloidal pyrite calcined at 500-550°C (CCPy) has a most promising potential for Cu(II) removal. The increase of pH, initial Cu(II) concentration and reaction time benefited the improvement of Cu(II) removal efficiency. The isothermal adsorption data of CCPy was well described by Langmuir isotherms and the thermodynamic parameters (ΔG<0, ΔH>0), indicating the endothermic nature of Cu(II) sorption on CCPy. The presence of most common ions in acid mine drainage and DO just had little influence on the Cu(II) uptake. The observation implied that CCPy is a low-cost, abundant material for Cu removal from Cu waters. 相似文献
18.
粘土矿物对胡敏酸的吸附行为研究 总被引：2，自引：0，他引：2
以蒙脱石和高岭土为吸附剂,分别与胡敏酸反应,研究胡敏酸在蒙脱石和高岭石上的吸附行为,并运用红外光谱、热重和Zeta电位等分析方法,表征分析了吸附前后的粘土矿物.实验结果表明,吸附过程受胡敏酸的初始浓度和pH值等因素影响;胡敏酸对粘土矿物的吸附等温线符合Freundlich等温方程;表征分析表明两种粘土矿物与胡敏酸复合体的红外光谱出现了C-H振动吸收峰;粘土矿物与胡敏酸结合后Zeta电位下降.实验的结果将有助于进一步探明环境中粘土矿物对胡敏酸的吸附机理. 相似文献
19.
Interaction of organic acids and pH on multi-heavy metal extraction from alkaline and acid mine soils 总被引：4，自引：0，他引：4
Y. Z. Ding Z. G. Song R. W. Feng J. K. Guo 《International Journal of Environmental Science and Technology》2014,11(1):33-42
Vegetation at mining sites can produce increased heavy metal leaching by the organic acids and protons originating from root secretion and litter degradation. Batch experiments were conducted to investigate the effects of organic acids and pH on the extraction of Pb, Cd, Zn and Cu from an alkaline mine soil (sampled from a mining site of Chenzhou City, Hunan Province) and an acid mine soil (sampled from a mining site of Daxin county, Guangxi Province). The results showed that in the presence of organic acids (acetic, oxalic, malic, fumaric, tartaric and citric acids) at pH 7, the extraction of Pb, Cd, Zn and Cu from the acid mine soil was much higher than that from the alkaline mine soil, in which only citric acid with higher concentration was capable of extracting some heavy metals. Citric acid had the strongest ability in extracting heavy metals, followed by oxalic acid. Heavy metal extraction dramatically decreased with increasing pH. Moreover, at low pH, oxalic acid promoted the risk of Cu leaching; at high pH, the leaching of Pb, Zn, Cd and Cu was enhanced by both oxalic and citric acids. This indicated that those plants, which can produce substantial citric acid or oxalic acid by root secretion and litter degradation, should not be selected for the revegetation of mining sites. 相似文献
20.
为了探究热活化过硫酸盐（PS）技术对水中氧氟沙星（OFX）的氧化降解作用,考察了反应温度、体系的初始pH、PS的初始浓度、OFX的初始浓度对OFX降解效果的影响;并在单因素实验的基础上,选取反应时间、体系的初始pH、PS的初始浓度和OFX的初始浓度4个因素进行了响应面优化实验。结果表明：最佳降解条件为,反应温度60℃、PS初始浓度4.0 mmol/L、pH=4.7、OFX初始浓度0.03 mmol/L、反应时间60 min,此时OFX的降解率为81.29%;4个因素对热活化PS降解OFX均有影响,其影响显著性从大到小为反应时间、OFX的初始浓度、PS的初始浓度、初始pH。利用响应曲面法模拟出反应体系的最佳条件,经实验验证,OFX降解率为93.78%,与预测最佳结果95.00%基本相符,表明模型可靠有效。 相似文献