黑腐酸对赤泥沉降分离过程影响的研究

进行了铝土矿中有机物黑腐酸对赤泥沉降性能影响的研究。考查了不同浓度条件下黑腐酸对赤泥沉降速度、溢流浮游物含量和底流压缩液固比的影响,探讨了絮凝剂消除黑腐酸负面作用的条件。     

赤泥微生物脱碱试验及机理探究

赤泥是制铝行业产生的碱性工业废渣，其强碱性是制约赤泥综合利用的主要因素。利用微生物对赤泥进行脱碱以降低赤泥对环境的危害。探究了巨大芽孢杆菌菌粉添加量、处理时间、液固比、培养方式及空气供应等条件对赤泥脱碱的影响。借助XRD、SEM分别对赤泥及脱碱渣进行矿相组成和表面形貌分析，利用HPLC对菌株进行产酸分析。结果表明，在赤泥用量20 g、菌粉添加量20 g、液固比7.5，震荡培养条件下，赤泥试样的pH可从10.3降至6.5左右，且最终可以保持在7.5；赤泥中主要的含碱矿物钙霞石衍射峰明显减弱，碳酸钙衍射峰加强；经过处理之后的脱碱渣物理结构更加规则；赤泥pH降低是微生物代谢产生的酸中和作用所致，巨大芽孢杆菌代谢有机酸主要为丙酸和苹果酸。     

拜耳法赤泥中主要组分分离研究

采用铵盐焙烧、水浸、酸浸等工艺对拜耳法赤泥进行处理,分离出了赤泥中的主要组分铁、铝、钙、硅,得到其相应的化合物:氧化铁、硫酸铝、石膏和水玻璃.研究了焙烧、水浸和酸浸工艺对拜耳法赤泥成分的影响,探索了从拜耳法赤泥中分离铁、铝、钙、硅的工艺方法和技术条件,分析了制备样品的化学成分和物相组成.     

拜耳赤泥制备水处理絮凝剂原液研究

以平果铝厂的拜耳赤泥及某冶炼厂废盐酸为原料,考察了酸过量系数、液固比、反应时间及反应温度对赤泥中Fe、Al浸出率的影响,得出用废盐酸浸出赤泥中Fe、Al获得制备水处理絮凝剂原液的较佳条件。     

拜耳赤泥制备水处理絮凝剂原液研究

以平果铝厂的拜耳赤泥及某冶炼厂废盐酸为原料,考察了酸过量系数、液固比、反应时间及反应温度对赤泥中Fe、Al浸出率的影响,得出用废盐酸浸出赤泥中Fe、Al获得制备水处理絮凝剂原液的较佳条件.     

硫酸/草酸体系下拜耳法赤泥中铁铝浸出行为的差异

为探清赤泥中的Fe、Al在硫酸/草酸体系中浸出行为差异，比较研究了两种酸浸体系下广西某铝厂拜耳法赤泥中Fe、Al的浸出规律及机制。主要考察了酸浸过程因素对Fe、Al浸出效果的影响，比较分析了最佳试验条件下拜耳法赤泥中Fe、Al在不同酸浸体系的浸出差异，并通过浸出动力学和热力学分析阐述了硫酸/草酸体系下Fe、Al的浸出过程机理。研究表明，试验条件下，硫酸对Fe、Al的浸出效果均优于草酸；酸性溶液中赤泥各元素的浸出具有阶段性，其中Al的浸出优先于Fe;硫酸/草酸体系中对Fe浸出的效果差异主要体现在无机酸酸根和有机酸酸根供电子能力和作用机制不同，对Al浸出的效果差异主要体现在对赤泥中铝氧化物的作用机制不同。这一发现对充分利用不同酸处理赤泥、优化分离提取赤泥中有价金属提供了新思路。     

赤泥中氧化铝和氧化铁的浸出

为回收赤泥中的铝和铁,解决赤泥污染和占地问题,研究了用盐酸溶出废赤泥中的氧化铝和氧化铁的工艺,考察了赤泥的焙烧、盐酸与赤泥的液固比、盐酸的浓度、酸浸时间、酸浸温度及酸浸方式对赤泥中氧化铝、氧化铁浸出率的影响.结果表明:赤泥不需要焙烧,盐酸与赤泥的液固比4∶1,盐酸的浓度为6mol/L,酸浸温度在109℃左右,酸浸时间为60 min,酸浸方式为二次浸出,氧化铝和氧化铁的浸出率分别为89.00%和98.39%.     

硫酸浸出赤泥富钛渣

制备了赤泥富钛渣,并通过单因素和正交试验考查了硫酸浓度、反应时间、反应温度对二氧化钛酸解率的影响。结果表明,影响二氧化钛酸解率因素的主次顺序为硫酸浓度、反应温度和反应时间。较佳酸化条件是反应温度180℃、反应时间140min和硫酸浓度95%,二氧化钛酸解率为96.32%。     

烧结法赤泥中有价金属分离试验研究

采用铵盐焙烧、水浸、酸浸工艺对烧结法赤泥进行处理,分离出有价金属铁、钙、钠、硅、钛,得到相应的化合物氧化铁、石膏、氯化钠、水玻璃和二氧化钛。研究了焙烧、水浸和酸浸工艺对烧结法赤泥成分的影响,探讨了从烧结法赤泥中分离铁、钙、钠、硅、钛的工艺,分析了制备产品的化学成分和物相组成。     

硫酸浸出赤泥渣回收二氧化钛的研究

对硫酸浸出赤泥渣的反应机理进行研究,参照晶粒模型将酸浸过程分为化学反应控制阶段、孔隙率控制阶段和传质扩散速率控制阶段,并通过试验对其进行了分析。通过正交试验考察了酸浸温度、硫酸浓度、酸浸时间和液固比(L/S)对二氧化钛浸出率的影响。最佳浸出条件为:酸浸温度150℃,硫酸浓度9mol/L,酸浸时间2h,L/S=6∶1。在此条件下,二氧化钛的浸出率达到了95.2%。     

Accumulation of Lathenum with Various Species in Oryzias Latipes Body

The accumulation and absorption kinetics of La by fish ( Oozias latipes) from both water and food were tested in fresh water. The effects of La concentration in water and food and the existence of fulvic acid on the absorption were investigated. It was demonstrated that the amount of La accumulated in fish increases with the increase in La concentration in water and food and exposure duration, which the normal physiological activity of fish was inhibited. With fulvic in the system, the absorption rate decreases significantly indicating that the fulvie combined La is not available to the fish uptake.     

Biological decomposition of fulvic acid preparations

Decomposition of preparations of various fractions of fulvic acids in pure cultures of bacteria and in the soil was investigated. In the soils enriched with fulvic acids the amount of bacteria increased, oxygen consumption and formation of carbon dioxide followed a typical sigmoid curve. The above measurements indicated that mineralization occurred after a very short or negligible lag phase. During the decomposition of fulvic acids the ability of microorganisms to oxidize aromatic compounds, e.g. vanillic and p-hydroxybenzoic acid, increased. The presence of aromatic structures in the used preparations of fulvic acids was demonstrated on the basis of their IR spectra and according to the results of chromatographic analyses of their hydrolysates. The results indicated a relationship between metabolism of fulvic acids and aromatic compounds. In samples of the soil preincubated with glucose with fulvic acids decomposed more rapidly than in untreated samples.     

腐殖酸在金矿形成过程中的作用

在实验室中直接从岩矿石样品中提取和分离了腐殖酸。一种是黑色胶状胡敏酸,它在pH小于3时沉淀。另一种是褐色可溶性富啡酸,它在酸碱范围内稳定。实验结果表明,富啡酸在pH为3～8.4之间对金有强烈溶解螯合作用。胡敏酸对金的吸附率达98％以上。腐殖酸是金的聚集体。它对金的富集不仅是胡敏酸吸附作用,更重要的是金与富啡酸同迁移共沉淀所致。因而,腐殖酸在金成矿过程中具有重要作用,是重要的有机地球化学因素。腐殖酸对金的富集作用是金地球化学行为非常重要的特性。     

Reduction of Fulvic Acid in Drinking Water by Ferrate

Acting as a powerful oxidant, efficient coagulant, and effective disinfectant, ferrate is a good multifunctional agent for water and wastewater purification. In this study, some of these key aspects were studied for treating water containing fulvic acid, including the reduction efficiency of fulvic acid (FA) in drinking water and the optimum conditions for reducing FA using ferrate prepared in the laboratory. Jar tests and pilot tests were employed in the studies and the results of FA reduction were analyzed spectrophotometrically. Ferrate in these tests exhibited good oxidation capacity on FA. The ultraviolet absorption (UVA) of 2 mg/L FA in water can be reduced about 90% when the weight ratio of ferrate to FA was 12:1. Adsorption to and coprecipitation with Fe(OH)3 precipitate produced by ferrate decomposition can also result in additional FA reduction. In the presence of turbidity, ferrate can oxidize and adsorb simultaneously and over 95% of UVA was reduced with the same weight ratio of 12:1. Combining the application of ferrate and polyaluminum chloride (PAC) or iron chloride (FeCl3) was more effective for FA reduction. The UVA of 2 mg/L FA was reduced 100% in synthetic drinking water by a joint treatment with 8 mg/L ferrate (FeO42? by weight) and 0.8 mg/L PAC (Al by weight) or 6 mg/L ferrate (FeO42? by weight) and 0.8 mg/L Fe3+ (Fe by weight). The pilot test performed more effectively for FA reduction than did the jar test.     

Hydrophobicity and Molecular Size Distribution of Unknown TOX in Drinking Water

The analysis of total organic halogen (TOX) in drinking water indicates that a substantial amount of the halogenated compounds cannot be accounted for by known specific disinfection by-products (DBPs). The primary aim of this research was to characterize the hydrophobicity and molecular size distribution of the unknown halogenated DBPs using XAD resins and ultrafiltration membranes. The impact of membrane rejection on the size analysis of unknown TOX was also investigated using chlorinated fulvic acid. Six finished waters from different locations and treatment processes were collected and fractionated into various hydrophobicity and molecular size groups. The results showed that most unknown TOX was in the size range between 0.5?kDa and 10?kDa, but it could have a wide spectrum of hydrophobicities. Simple ultrafiltration was not always reliable as a characterization tool, as it was shown to reject a significant fraction of DBPs with molecular weight (MW) lower than the membrane cutoffs. Flushing with deionized water was effective in removing these low MW compounds from the ultrafiltration cell. A significant reduction in the apparent size of unknown TOX resulted when low MW DBPs were flushed out of the cell (comparing with classic parallel ultrafiltration). Coagulation of fulvic acid also significantly reduced the apparent size of unknown TOX formed by chlorine.     

Extradural temporopolar approach for giant pituitary adenomas invading the cavernous sinus and parasellar regions]

Natural organic matter (NOM) was extracted from a raw water source (Forge Pond, Granby, Mass.) and fractionated into eight groups: fulvic acid, humic acid, hydrophilic acid, weak hydrophobic acids, hydrophilic neutrals, hydrophobic neutrals, hydrophilic bases, and hydrophobic bases. The extent of adsorption of these fractions on preformed aluminum hydroxide flocs was determined. Also, the adsorption affinities of various fractions were correlated to selected NOM properties, i.e., organic charge, molecular weight, and specific ultraviolet absorbance. The nature of the reactions leading to adsorption was discussed, along with the induced dissolution of aluminum from the floc surface and its resulting association with NOM in particulate or colloidal forms.     

Microbial activity in soil enriched with preparations of AS-lignin and lignofulvonic acid

In chernozem soil, enriched with preparations of AS-lignin or lignofulvonic acid, an increased production of carbon dioxide was observed during a 4-week incubation, and, as compared with the non-amended control, an increased number of bacteria but not of actinomycetes was detected. Increased numbers of fungi were detected only in the variant with AS-lignin at the end of the incubation. The relative incidence of bacteria utilizing vanillin, syringic acid or protocatechuic acid as the only carbon sources increased in the enriched medium. Oxidation of vanillic acid, syringic acid and to a lesser extent of coumarin increased in suspensions of soils incubated with AS-lignin or fulvic acid. The results obtained indicate that bacteria are involved in the mineralization of the added substrates and confirm the relationship between metabolism of these compounds and simple aromatic derivatives.     

Effects of Ce^3＋ on improvement of spectral characteristics and function of chloroplasts damaged by linolenic acid in spinach

Linolenic acid has great effects on the structure and function of chloroplast. We studied the effects of Ce3+ on the improvement of chloroplast spectral characteristics and oxygen evolution damaged by linolenic acid in spinach. Results showed that Ce3+ could decrease the light absorption increased by linolenic acid and promote the distribution of excitation energy to PS Ⅱ and alleviate the decrease of PS Ⅱ fluo-rescence yield caused by linolenic acid. The linolenic acid treatments in various concentrations reduced the oxygen-evolving rate of chloro-plasts, but the rate was accelerated since adding Ce3+.     

316L不锈钢纤维在硫酸介质中的腐蚀行为

利用失重法对316L不锈铜纤维在硫酸介质中的腐蚀情况进行了研究，探讨了硫酸的浓度、温度对腐蚀速率的影响，以及硫酸浓度对转变时间的影响。实验结果表明材料的腐蚀速率随温度升高而增大，硫酸浓度在30％～40％之间时腐蚀速率出现峰值，之后随硫酸浓度增大腐蚀速率逐渐减小。