共查询到20条相似文献，搜索用时 78 毫秒
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硼泥处理电镀废水中铬(Ⅵ)的研究 总被引：5，自引：0，他引：5
本文采用硫酸亚铁还原,硼泥絮凝沉降的方法处理电镀废水中的铬（Ⅵ）．控制还原时的ｐＨ值为 ３．５～５．５,铬（Ⅵ）：硫酸亚铁：硼泥二１：２０：１４０（重量比）,铬（Ⅵ）去除率达９９％以上．对于铬（Ⅵ）浓度小于１０００ｍｇ／Ｌ的废水,经一次处理,就可以达到国家的排放标准． 相似文献
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简述了实验室铬洗液废水造成的危害,总结了利用化学法、电解法、离子交换法、膜分离法、吸附法、生物法和黄原酸酯等方法处理铬废水的特点和存在问题,提出了生物法是处理铬废水的发展方向。 相似文献
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焦永侠 《淮南职业技术学院学报》2007,7(4):96-98
介绍了活性炭、石灰乳和铁屑法处理镀锌废水的基本原理、工艺流程和工艺流程中的各项试验参数:活性炭与铁屑投料比(按重量)0.7 ∶1,废水中PH控制,酸性溶液PH<3,碱性溶液PH为7～8;处理后的废水中含Zn2+1.85 mg·L-1,PH为7～8;同时采用低价铬的纯化,达到了节能的目的;处理后的废水中锌含量达到国家排放标准,处理后的废水可回收利用;提出了废水处理中应注意的问题. 相似文献
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陈禹银 《乐山师范学院学报》2006,21(12):42-44
采用碳酸钙与少量氧化镁对含铬废水进行除铬处理。实验考察了碳酸钙及氧化镁的用量、搅拌时间、温度及pH值对处理结果的影响,探讨了碳酸钙处理含铬废水的机理。结果表明,在pH为2-3范围内,吸附处理剂用量:碳酸钙约9g.L-1和氧化镁约0.09g.L-1,搅拌时间30min,常温下操作,铬的去除率可达99%以上。对含铬在10mg.L-1左右的废水,一次处理即可达标排放。使用过的碳酸钙与氧化镁回收后,可再次用于处理含铬废水。 相似文献
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改性木屑处理含铬重金属废水的研究 总被引：1，自引：0，他引：1
用NH4Fe(SO4)2溶液对木屑进行改性,并将其应用于含铬废水的处理,探讨了木屑用量、pH值、处理时间、温度等因素对铬离子去除率的影响.结果表明,经改性处理过的木屑在用量为40 g/L,pH值为2,吸附时间为60min,吸附温度为30℃的条件下,处理含铬废水的去除率可达70%左右;在调节pH值和溶入的Fe3 所产生的絮凝作用下,可使去除率达99%. 相似文献
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用多胺类物质制备了高分子絮凝剂PXM,用于对含Cr3+废水的处理,考察了反应时间、pH值、絮凝剂加入量对含Cr3+废水处理的影响.实验表明:在pH值为6.5、PXM加量31.5mg/L.处理时间为9min的条件下,对铬的去除率可达98.0%以上,处理后的废水可以直接排放.并对去除Cr3+的反应机理做了初步探讨. 相似文献
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还原中和共沉淀法处理实验室铬洗液废水的研究 总被引：3，自引：0，他引：3
以某高校的实验室洗液废水和几种代表性废液混合液为试验对象,用还原中和共沉淀法对废水中的铬进行毒性降解试验。结果表明:废液的pH、还原剂种类、还原剂的投加量等对铬的去除率有一定的影响。经处理后的出水虽不能严格达到国家污水排放标准,但由于其设备、操作简单,实际应用性强。 相似文献
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铁氧体法处理含铬和隔废水及其含量测定 总被引：5，自引：0，他引：5
本文介绍一体现绿色化学的无机与分析化学的综合与设计实验,即用铁氧体法同时处理废水中的铬和镉,由可见分光光度法和原子吸收分光光度法测定处理前后废液中６价铬、总铬和镉的浓度。通过本实验,可使工科化工类学生掌握多种基本操作技术和无机物分析中常用仪器的使用方法,增强环境保护意识、培养他们综合与独立进行科学实验的初步能力。 相似文献
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采用化学氧化还原-中和-絮凝沉淀法处理电镀废水中铬,研究了还原pH值、絮凝pH值、絮凝剂的用量、沉降时间对处理效果的影响.还原六价铬的最佳pH在2.0～2.2之间时,絮凝最佳pH值为9时,加入PAM,絮凝时间为0.5小时絮凝效果最好,处理后的Cr浓度最小. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献