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61.
62.
通过采用聚合氯化铝铁(PAFC)、氯化铁(FeCl3)及聚合硫酸铁(PFS)对含镉废水的处理研究表明,三种混凝剂对含镉水体均有良好的处理效果,同等条件下,三种混凝剂对含镉水体去除率分别为98.22%、92.19%和93.63%。研究了PAFC对含镉水体的混凝沉淀效果,实验结果表明:碱性条件有利于镉离子的沉淀,当pH为9~11时,去除率可达98.00%左右;对于初始浓度为4.000 0 mg.L-1的含镉废水,经处理后,水体浓度可降至0.184 0 mg.L-1,对于初始浓度为0.400 0 mg.L-1的含镉废水,经处理后水体浓度降至0.007 2 mg.L-1;废水中投加一定量的石灰乳对PAFC除镉起一定的作用,投加量达30.00 mg.L-1时,其去除率达99.91%;通过对PAFC除镉动力学拟合,符合一级线性动力学方程。 相似文献
63.
FeⅡ(EDTA)络合协同RDB去除NO废气效能及过程分析 总被引:1,自引:0,他引:1
为进一步提高一氧化氮(NO)的去除效率,在新型生物转鼓反应器(rotating drum biofilter,RDB)中,以FeⅡ(EDTA)络合协同RDB生物转鼓的耦合技术强化难水溶性NO的气液传质速率,提高生物还原效能为目标进行了研究.结果表明,适量FeⅡ(EDTA)被添加到RDB底部营养液后,能迅速吸收气相中的NO并生成FeⅡ(EDTA)-NO络合物,进而可通过反硝化实现同步脱氮和络合剂再生.在转速0.5 r.min-1、空床停留时间(EBRT)57.7 s、温度30℃、pH 7~8的实验条件下,RDB的净化效能随络合剂的投加而显著改善;FeⅡ(EDTA)质量浓度从0增至500 mg.L-1后,NO去除率从61.1%提高到97.6%,去除负荷从16.2 g.(m3.h)-1上升到26.7 g.(m3.h)-1.分析了FeⅡ(EDTA)络合协同净化NO的反应过程,建立了NO净化效率与FeⅡ(EDTA)添加浓度的关联方程,可较好地拟合实验数据. 相似文献
64.
为了解电解铝厂氟污染对周边蔬菜的影响,通过采用氟离子选择电极法对凯里某电解铝厂周边蔬菜的氟含量进行测定,并对蔬菜的氟含量特征进行分析。结果表明:铝厂周边蔬菜中氟的含量最高为76.94 mg/kg,最低为19.90 mg/kg,平均含量为42.98 mg/kg,都已超过国家食品卫生标准规定的蔬菜中氟污染物最大容许含量,蔬菜受到了较为严重的氟污染。不同种类蔬菜中的氟含量存在较大差异;叶菜类蔬菜氟含量为茄果类蔬菜氟含量的1.5倍,叶菜类蔬菜积累氟的能力比茄果类蔬菜强,更容易受到氟的污染。铝厂周边不同区域的蔬菜都受到比较严重的氟污染,主要与铝厂的距离有关,距离铝厂越近,蔬菜受到氟污染更严重。 相似文献
65.
胶州湾及邻近海域表层海水中一氧化氮浓度分布及其影响因素探讨 总被引:1,自引:1,他引:0
2011年2~3月利用化学发光法对胶州湾及邻近海域表层海水中一氧化氮(NO)浓度进行了监测.结合水文、化学和生物等要素的同步观测资料,对该海域NO浓度分布及其影响因素进行了探讨.结果表明,胶州湾内表层海水中NO浓度为0.080~0.493 nmol.L-1,平均值为(0.292±0.146)nmol.L-1,胶州湾外NO浓度为未检出~0.435 nmol.L-1,平均值为(0.160±0.130)nmol.L-1.总体来说,胶州湾表层海水中NO浓度呈现出自湾内向湾外递降的分布趋势,陆地径流和人为活动可能对NO浓度的分布造成一定程度的影响.胶州湾及邻近海域表层海水中NO浓度比开阔大洋高1个数量级.周日变化研究表明,NO浓度具有一定的变化特征,最大值出现在15:00,这可能主要受光照的影响.影响NO浓度分布的因素比较复杂,可能主要受亚硝酸盐、光强和pH等因素的影响.结果表明,2011年春季胶州湾及邻近海域表层海水是大气NO的源,通量约为1.09×10-15 mol.(cm2.s)-1. 相似文献
66.
Effects of long-term amendment of organic manure and nitrogen fertilizer on nitrous oxide emission in a sandy loam soil 总被引:3,自引:0,他引:3
To understand the effects of long-term amendment of organic manure and N fertilizer on N2O emission in the North China Plain, a laboratory incubation at different temperatures and soil moistures were carried out using soils treated with organic manure (OM), half organic manure plus half fertilizer N (HOM), fertilizer NPK (NPK), fertilizer NP (NP), fertilizer NK (NK), fertilizer PK (NK) and control (CK) since 1989. Cumulative N2O emission in OM soil during the 17 d incubation period was slightly higher than in NPK soil under optimum nitrification conditions (25℃ and 60% water-filled pore space, WFPS), but more than twice under the optimum denitrification conditions (35℃ and 90% WFPS). N2O produced by denitrification was 2.1-2.3 times greater than that by nitrification in OM and HOM soils, but only 1.5 times greater in NPK and NP soils. These results implied that the long-term amendment of organic manure could significantly increase the N2O emission via denitrification in OM soil as compared to NPK soil. This is quite different from field measurement between OM soil and NPK soil. Substantial inhibition of the formation of anaerobic environment for denitrification in field might result in no marked difference in N2O emission between OM and NPK soils. This is due in part to more rapid oxygen diffusion in coarse textured soils than consumption by aerobic microbes until WFPS was 75% and to low easily decomposed organic C of organic manure. This finding suggested that addition of organic manure in the tested sandy loam might be a good management option since it seldom caused a burst of N2O emission but sequestered atmospheric C and maintained efficiently applied N in soil. 相似文献
67.
The catalyst of Fe-Mo/ZSM-5 has been found to be more active than Fe-ZSM-5 and Mo/ZSM-5 separately for selective catalytic reduction (SCR) of nitric oxide (NO) with NH3. The kinetics of the SCR reaction in the presence of O2 was studied in this work. The results show that the observed reaction orders were 0.74-0.99, 0.01-0.13, and 0 for NO, O2 and NH3, respectively, at 350-450℃. And the apparent activation energy of the SCR was 65 kJ/mol on the Fe-Mo/ZSM-5 catalyst. The SCR mechanism was also deduced. Adsorbed NO species can react directly with adsorbed ammonia species on the active sites to form N2 and H2O. Gaseous O2 might serve as a reoxidizing agent for the active sites that have undergone reduction in the SCR process. It is also important to note that a certain amount of NO was decomposed directly over the Fe-Mo/ZSM-5 catalyst in the absence of NH3. 相似文献
68.
目的 了解炼铝作业氟的危害状况,为工业性氟病的防治提供依据.方法 对氟作业环境作职业卫生学调查.采用剂量患病率寿命表法对866名电解铝作业工人工业性氟病的发病情况进行流行病学调查,并作相关回归分析.结果 该厂接氟工人工业性氟病的总患病率为1.73%,且患病率随累积接氟量的增加而升高,呈高度正相关(r=0.997,P<0.01).并据所求得回归方程(y=10.34InD-18.21)推算出接氟工人控制患病率时的允许连续工作年限和今后的发病趋势.结论 该厂电解铝车间氟危害较重,应加强卫生防护措施,并建议将车间氟最高容许浓度从目前1 mg/m3降为0.5 mg/m3为宜. 相似文献
69.
Effect of C/N ratio, aeration rate and moisture content on ammonia and greenhouse gas emission during the composting 总被引:3,自引:0,他引:3
Gaseous emission (N2O, CH4 and NH3) from composting can be an important source of anthropogenic greenhouse gas and air pollution. A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio, aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system. The results showed that about 23.9% to 45.6% of total organic carbon (TOC) was lost in the form of CO2 and 0.8% to 7.5% of TOC emitted as CH4. Most of the nitrogen was lost in the form of NH3, which account for 9.6% to 32.4% of initial nitrogen. N2O was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it. Statistic analysis showed that the aeration rate is the most important factor which could affect the NH3 (p = 0.0189), CH4 (p = 0.0113) and N2O (p = 0.0493) emissions significantly. Higher aeration rates reduce the CH4 emission but increase the NH3 and N2O losses. C/N ratio could affect the NH3 (p = 0.0442) and CH4 (p = 0.0246) emissions significantly, but not the N2O. Lower C/N ratio caused higher NH3 and CH4 emissions. The initial moisture content can not influence the gaseous emission significantly. Most treatments were matured after 37 days, except a trial with high moisture content and a low C/N ratio. 相似文献
70.