高含铁废酸液处置工程实例

某煤业有限公司清洗锅炉产生的废液中含有大量的铁离子与H^+,具有腐蚀性危险特性,属于危险废物。本工程实例利用酸碱中和及氧化絮凝沉淀的原理,消除了该废酸液的腐蚀性危险特性,同时降低了废酸液中的铁离子以及废酸液的色度、浊度,为后续的深度治理提供了便利。对高含铁废酸液的治理有一定的借鉴意义。     

Electroactive polyamide modified carbon paste electrode for the determination of ascorbic acid

Construction electroactive polyamide (EPA) with aniline-pentamer-based in the main chain has been modified on the surface of carbon paste electrode (CPE) for detecting ascorbic acid (AA). Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy studies confirm the well-defined molecular structure of the oligoaniline and EPA. Further, the in situ chemical oxidation of EPA was monitored by UV-Visible absorption spectrum. The electroactivity of the EPA was evaluated by performing electrochemical cyclic voltammetry study. The sensing response studies have revealed that this EPA-modified CPE electrode can detect AA in the range of 0.05–0.7 mM with detection limit of 0.005 mM and sensitivity of 1.5 × 10^–5 AmM^–1. Besides, this EPA-modified CPE electrode shows a minimal relative standard deviation of 1.73%.     

Tolerance of S. cerevisiae and Z. mobilis to inhibitors produced during dilute acid hydrolysis of soybean meal

The objective of this research was to determine the minimum inhibitory concentration of 5-hydroxymethyl furfural, furfural, and acetic acid on Saccharomyces cerevisiae (NRRL Y-2233) and Zymomonas mobilis subspecies mobilis (NRRL B-4286) in both detoxified hydrolyzed soybean meal and synthetic YM broth spiked with the three compounds. Soybean meal was hydrolyzed with dilute sulfuric acid (0.0, 0.5, 1.25, and 2.0% wt v^?1) at three temperatures (105, 120, and 135°C) and three durations (15, 30, and 45 min) followed by detoxification with activated carbon. Of all the combinations, only the treatments obtained at 135°C, 2.0% H₂SO₄, and 45 min and the one at 135°C, 1.25% H₂SO₄, and 45 min showed inhibition in the growth of the tested microorganisms. Spiked YM broths showed inhibition for the highest levels of inhibitors, either applied individually or in combination.     

失效磷酸基化学抛光液的再生

采用氟铝酸钠沉淀法去除失效磷酸基化学抛光液中的铝杂质,并对溶液再生利用的工艺条件进行了研究.实验结果表明,在氢氧化钠和氢氟酸加入量与理论值的比均为1.2(即n(氢氧化钠):n(Al~(3+)):2:1、n(氢氟酸):n(Al~(3+))=28:5)的条件下,采用二步法过滤后,抛光液中磷酸质量分数大于50%,磷酸回收率为79.5%,Al~(3+)去除率为97.1%,剩余Al~(3+)质量分数为0.05%.滤渣经处理后成为新的有价物质,滤液在补加磷酸和其他有效成分后可再生循环使用.     

Model Evaluation of Dry Deposition to Vegetation for Volatile and Semi-Volatile Organic Compounds in a Multimedia Environment

Gas-phase atmospheric deposition wasevaluated in a screening level model of themultimedia environmental distribution of toxics(MEND-TOX). Algorithmic additions to MEND-TOXfor the estimation of gas-phase depositionvelocity over vegetated surfaces were analyzedusing recently published dry deposition fluxmeasurements for nitric acid. Model outputs arecompared to similar estimates from the NOAAmultilayer dry deposition model. Results of theevaluation indicate that MEND-TOX performs wellas a screening level model for the estimation ofgas-phase dry deposition velocity of nitric acidover soybeans. The present study expandsprevious laboratory results for organic speciesto include an inorganic species and open fieldand dry leaf, conditions.(On assignment to the National Exposure Research Laboratory, U.S. Environmental Protection Agency); (author for correspondence, e-mail     

Much Ado: How Big Is the Problem of Hydrolysis of Methyl Tertiary Butyl Ether (MtBE) to Form Tertiary Butyl Alcohol (tBA)?

Groundwater contaminated by the gasoline additive methyl tertiary butyl ether (MtBE) is also frequently impacted by tertiary butyl alcohol (tBA). The USEPA recently sponsored a study that discusses the possibility of hydrolysis of MtBE to form tBA during analytical procedures. This finding is important because it suggests that existing tBA data may not accurately depict tBA or MtBE concentrations in groundwater. This article discusses the mechanism and kinetics of MtBE hydrolysis, then presents three case studies of analytical results from sites in California, USA. Although these case studies are limited in scope, the data do not support the occurrence of the hydrolysis of MtBE to form tBA due to acid preservation of groundwater samples. At a minimum, this suggests that MtBE hydrolysis may not be as pervasive a problem as suggested in USEPA's study; therefore, concerns about the validity of historical tBA data may not be warranted. The reason for this result may be simple: there are two necessary factors that promote hydrolysis: low pH and high temperature (above 40°C). Although the static headspace analysis method used to obtain the data in the White et al. study may require heating to achieve adequate sensitivity, many laboratories perform purge-and-trap analyses without heating. Under those conditions, hydrolysis may not occur. However, it may be prudent to preserve samples with alkaline preservatives, to eschew high temperatures during the analysis of groundwater samples, or to neutralize the sample pH before heating.     

Evaluation of soil characteristics potentially affecting arsenic concentration in paddy rice (Oryza sativa L.)

Paddy rice may contribute considerably to the human intake of As. The knowledge of soil characteristics affecting the As content of the rice plant enables the development of agricultural measures for controlling As uptake.During field surveys in 2004 and 2006, plant samples from 68 fields (Italy, Po-area) revealed markedly differing As concentration in polished rice. The soil factors total As_{(aqua regia)}, pH, grain size fractions, total C, plant available P_(CAL), poorly crystalline Fe_(oxal.) and plant available Si_(Na-acetate) content that potentially affect As content of rice were determined.A multiple linear regression analysis showed a significant positive influence of the total As_{(aqua regia)} and plant available P_(CAL) content and a negative influence of the poorly crystalline Fe_(oxal.) content of the soil on the As content in polished rice and rice straw.Si concentration in rice straw varied widely and was negatively related to As content in straw and polished rice.     

酸性矿井水的治理方法研究进展

酸性矿井水污染已成为全球范围内较为严重的环境污染问题之一,其污染范围广泛,诱因复杂,性质多变,危害深远。酸性矿井水未经处理排放造成江湖河流酸化,地表土壤板结,水中及土壤中的重金属含量超标,导致生物体内重金属过量富集,作物死亡,从而严重地危害了人类的健康和生命安全。对于酸性矿井水的治理意义重大,刻不容缓。讨论了目前国内外常见的酸性矿井水污染的治理技术方法,并对各种方法进行了比较。     

Thermal treatments of industrial wastes in controlled atmospheres for the elimination of As, Hg, Cd, Se and the concentration of Pb, Cu and Zn

Thermal treatments of five different types of non-ferrous metallurgical wastes, under a controlled atmosphere, were carried out at temperatures lower than 800°C for the separation of their toxic compounds and the concentration of valuable metals in the treatments residues. The best results were obtained by the treatments in air or hydrogen, or both successively. Simple treatments, using air or hydrogen, of three samples allowed the elimination of more than 95% of their toxic elements and almost doubled their valuable metals concentration. For the rest of the samples, a combined treatment was necessary for their efficient decontamination. In this case, the valuable metals content in the treatment's residue was increased to a reasonable value. Most of the solids issuing from these treatments can be recycled in current non-ferrous metallurgical processes.     

Induction of glutathione reductase enzyme activity by β‐aminobutyric acid in plant leaves

Abstract

Treatment of pea and tobacco leaf discs with the resistance inducer DL‐β‐amino‐n‐butyric acid (BABA) led to a substantial induction of glutathione reductase (GR, E.C. 1.6.4.2.) enzyme activity. After exposure to 1 mM BABA for 96 hrs, the GR activities were 3.2‐fold and 2.9‐fold higher in pea and tobacco leaf discs, respectively, than GR activities in untreated controls. Elevated GR levels may contribute to the antioxidative protection of plants during pathogen attack.