首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 93 毫秒
1.
聚合硅酸铝铁絮凝剂的制备及其水解和絮凝特性   总被引:3,自引:0,他引:3  
聚合硅酸铝铁(PAFSC)作为一种新型絮凝剂,它保留了铝铁各自均聚物的优点,克服了聚合氯化铝(PAC)处理水样时残余铝含量较高和聚合氯化铁(PFC)稳定性较差的缺点.本文利用共聚和复合两种工艺制备PAFSC,研究Al/Fe/Si摩尔比和碱化度(B)对絮凝效果的影响.  相似文献   

2.
<正>在电厂行业检测过程中,水中常规阴阳离子是重要的监控项目,而且对于浓度的要求极其苛刻.浓度低至(μg·l-1)级的痕量氯离子和硫酸根离子就能腐蚀破坏发电站设备中的不锈钢部件,如锅炉、锅炉管、凝汽器管道以及涡轮叶片.这主要是由于离子组分集中于蒸汽循环空间内会引起应力裂纹,粒间碰撞和凹痕.而裂纹和凹痕会进一步造成设备严重腐蚀。  相似文献   

3.
陶瓷球颗粒在圆形漏斗中下落速度的PIV研究   总被引:1,自引:0,他引:1  
利用PIV(粒子图像测速技术)对重力作用下陶瓷球颗粒在圆形漏斗底部出口下落的速度场进行了测量和分析.分别测量了漏斗中陶瓷球颗粒在不同起始颗粒层高度下出口处的速度、同一起始颗粒层高度下不同漏斗底部出口大小时的速度和同一出口条件下不同粒径时的速度.对不同下落高度时陶瓷球的下落速度进行了比较.结果表明,不同起始颗粒层高度对陶瓷球速度没有影响,同一粒径陶瓷球,颗粒速度随着出口的增大而增大;同一底部出口时,颗粒速度随着粒径的减小而增大.  相似文献   

4.
陶瓷行业是国民经济和社会发展的重要基础材料,也是我国实现双碳目标的重要工业行业。全国碳市场启动以来,电力行业由广东试点市场转入全国碳市场交易,陶瓷作为高碳排放行业,已经确定作为下一批纳入广东试点市场的行业之一。基于陶瓷企业工艺特点,结合各碳交易试点陶瓷行业配额分配方法,以及广东省陶瓷企业碳排放核算方法和现行其他行业碳排放配额分配方案,采用基准法结合历史强度法或全部采用历史强度法是广东省陶瓷企业碳排放配额的选择方向,同时在配额分配时可以考虑兼顾能源结构优化的鼓励政策。  相似文献   

5.
魏清莲  吴善良 《环境化学》2000,19(4):324-329
研究了制备蜂窝陶瓷涂层使用的Al2O3胶液的触变性以及影响胶液触变性的因素,并对胶液的触变性对蜂窝陶瓷涂层上涂量的影响进行了探讨,结果表明,影响胶液触变性最大的因素是含固量:若使胶液具有触变性,含固量只能在一定范围内波动,且含固量较高,胶液的触变性越明显;稳定剂、表面活性剂以及醋酸都影响胶液的触变性;而胶液的触变性有利于蜂窝陶瓷涂层的上涂量的提高。  相似文献   

6.
研究了制备蜂窝陶瓷涂层使用的AL_2O_3胶液的触变性以及影响胶液触变性的因素,并对胶液的触变性对蜂窝陶瓷涂层的上涂量的影响进行了探讨 结果表明,影响胶液触变性最大的因素是含固量:若使胶液具有触变性,含固量只能在一定范围内波动,且含固量越高,胶液的触变性越明显;稳定剂、表面活性剂以及醋酸都影响胶液的触变性;而胶液的触变性有利于蜂窝陶瓷涂层的上涂量的提高.  相似文献   

7.
选择太湖梅梁湾的表层沉积物作为实验对象,研究了水动力与表面活性剂协同作用下,双酚A吸附行为的变化特征.结果表明,当CTMAB(十六烷基三甲基溴化铵)浓度在1.0倍临界胶束浓度(CMC)以下时,切应力的改变对双酚A在沉积物上的吸附量基本无影响;其吸附量随CTMAB浓度的增大而增大,0.1倍CMC、0.5倍CMC和1.0倍CMC的CTMAB条件下,双酚A的吸附量较0 CMC分别增大了0.18倍、0.54倍和0.62倍;相对于Freundich模型,其吸附等温线更符合线性模型.当CTMAB浓度高于CMC时,双酚A在沉积物上的吸附量和吸附平衡时间均随切应力的增加而减小,在切应力和低浓度CTMAB共同作用时,以切应力促进吸附平衡作用为主;而当切应力和高浓度CTMAB共同作用时,以CTMAB的作用为主.水动力和CTMAB共同作用下的双酚A的吸附过程满足准二级吸附动力学方程.  相似文献   

8.
沉积物再悬浮-重金属释放机制研究进展   总被引:16,自引:0,他引:16  
俞慎  历红波 《生态环境》2010,19(7):1724-1731
水-沉积物界面重金属迁移和转化行为已成为水环境质量研究的热点。因自然、生物、人为活动等驱动的沉积物再悬浮使得沉积物颗粒吸附和结合的重金属可能通过吸附-解吸平衡和氧化还原反应而释放进入上覆水体。随着外在污染源输入逐步得到控制,沉积物再悬浮释放重金属将成为水体重要的内在污染源而对水环境质量和水生生物产生影响。本文综述了最近几年的相关研究文献,对沉积物再悬浮的动力来源及发生机制、再悬浮-重金属释放机制及主要影响因素进行了阐述,探讨了该领域未来可能的研究方向。相关研究发现,当干扰切应力大于沉积物的临界切应力值时,沉积物再悬浮发生,且再悬浮颗粒量随干扰切应力的增强而增大;再悬浮使还原态沉积物暴露于有氧环境,有机质和硫化物的氧化是沉积物结合态重金属释放的主要机理,而沉积物颗粒电性吸附的重金属则通过解吸进入水体;切应力大小、再悬浮水体理化性质、沉积物理化性质以及微生物活性等因素调控着沉积物吸附态或结合态重金属的释放。本文指出再悬浮沉积物释放重金属的去向(再分配机理)以及再悬浮-重金属释放的动力学过程、沉积物悬浮-重金属释放复合预测模型的建立、沉积物悬浮-释放重金属的生物可利用性及生物毒害评价将是本领域需要进一步研究的重点。  相似文献   

9.
采用中空纤维膜接触器进行了从模拟“铜洗再生气”中脱氨的研究,探讨了影响脱除效率的主要因素.试验表明:膜吸收法对混合气中的氨有很好的脱除效果,当混合气中氨的浓度为20.0g·Nm-3,膜组件的处理能力为5.1Nn3·m-2·h-1时,脱氨率大于99.9%,即脱氨后氨的浓度低于0.02g·Nm-3.当组件内吸收液供应充足时,分离过程的传质阻力主要在膜和气体一侧.研究发现,当用挥发性水溶液(盐酸)作为吸收剂时,由于NH4Cl晶体的桥联作用导致疏水性微孔膜亲水化.  相似文献   

10.
上海化学工业区土壤重金属元素形态分析   总被引:73,自引:3,他引:73  
选取上海化学工业区土壤背景值样品,采用Tessier A连续提取法研究土壤中6种重金属元素的形态分布。研究结果表明,在该化工区土壤中,Cd主要以可交换态和铁锰氧化物结合态为主,分别占总量的41.5%和36.7%,说明元素Cd较活泼,具有潜在的环境影响能力,应该给予更多的关注;Cr、Cu、Ni和Zn等4种元素主要以有机结合态和残余态为主,两者分别占总量的41.4%、58.9%、31.4、32.5%和45.9%、31.5%、57.4%、52.3%;而Pb则主要以有机结合态形式存在,其占总量的87.8%;元素形态分析表明Cr、Cu、Ni、Zn和Pb这5种元素相对比较稳定。  相似文献   

11.
镉对籽粒苋耐性生理及营养元素吸收积累的影响   总被引:3,自引:0,他引:3  
李虹颖  苏彦华 《生态环境》2012,21(2):308-313
初步阐明了镉对籽粒苋耐性生理及营养元素吸收积累的影响,为进一步揭示籽粒苋的镉耐性与镉富集机理奠定了基础。通过对生物量的监测,对叶绿素、蛋白质、游离氨基酸、大量元素及微量元素等的含量的测定,阐明镉胁迫对籽粒苋生长生理、抗胁迫耐性、营养元素吸收分配的影响。研究结果显示,镉胁迫对籽粒苋的生长抑制作用不明显,植株生物量随着镉浓度的提高而轻微降低。随着镉处理浓度的提高,叶绿素含量下降幅度显著;蛋白质和游离氨基酸含量变化幅度不明显;钾含量无大幅变化;镉、磷、钙、镁、锌、铁、锰、铜含量变化幅度较显著。镉、钾、磷、锰的迁移系数随着镉处理浓度的提高无显著变化;钙的迁移系数呈上升趋势;镁、锌、铁、铜的迁移系数均呈下降趋势。这些结果表明:镉胁迫降低籽粒苋叶绿素含量,抑制植株光合作用,继而抑制了植株的生长,但其程度不明显;镉胁迫条件启动活性氧防御机制;引起植株体内部分养分代谢紊乱。结论:低浓度镉处理条件下,籽粒苋受镉离子影响,抗氧化能力下降。在高浓度镉处理条件下,籽粒苋调节了营养元素的吸收和分配,启动了一系列活性氧防御机制,提高了抗胁迫能力。  相似文献   

12.
低温胁迫下香菇基因表达差异研究   总被引:2,自引:0,他引:2  
香菇为变温结实型担子菌,为探讨低温胁迫诱导香菇子实体形成的分子机理,应用mRNA差异显示技术对低温胁迫下香菇菌丝体基因表达差异进行了比较.电泳差异展示结果表明,低温胁迫前后基因表达在数量水平和质量水平上都存在显著差异,数量水平的差异表现为低温胁迫过程中表达序列标签(expressed sequence tags,ESTs)增强表达或减弱表达;质量水平上的差异表现为低温胁迫使部分ESTs特异诱导表达或沉默表达.差异ESTs的类型比较和多态性分析发现,低温胁迫处理6~12h可能是诱发香菇原基发生的关键时段.本文还对显著差异表达的基因片段进行序列分析和Northern杂交验证,初步讨论了低温胁迫时间在调控香菇子实体发生中的作用.图4表2参13  相似文献   

13.
Dyes are common pollutants in textile wastewaters, and the treatment of the wastewater has now attracted much attention due to its wide application and low biodegradability. In this study, Fe0/C/Clay ceramics, a kind of novel micro-electrolysis filler, were sintered and employed in a dynamic micro-electrolysis reactor for synthetic Acid Red 73 (AR73) and Reactive Blue 4 (RB4) wastewater treatment. The effects of influent pH, hydraulic retention time (HRT), and aeration on the decoloration efficiencies of AR73 and RB4 were studied. The optimum conditions for wastewater treatment were: AR73, influent pH of 4, HRT of 2 h and aeration; RB4, influent pH of 5, HRT of 6 h and aeration. Under the optimum conditions, decoloration efficiency of AR73 and RB4 wastewater was 96% and 83%, respectively. Results of UV-vis spectrum scanning demonstrated that the chromophores were broken. Continuous running tests showed that improvement of micro-electrolysis system with Fe0/C/Clay ceramics for AR73 and RB4 synthetic wastewater treatment could avoid failure of micro-electrolysis reactor, which indicated great potential for the practical application of the ceramics in the field of actual industrial wastewater treatment.  相似文献   

14.
15.
This report shows that soil heavy metals can be totally immobilized by grinding with nano-Fe/Ca/CaO. Remediation of soils contaminated by heavy metals is a critical issue in Japan. Indeed, contaminated soils are notoriously difficult to remediate using available technologies. Major setbacks in typical immobilization techniques for heavy metals are wet conditions, forming secondary effluents and further treatment for effluents. Solidification with nano-Fe/Ca/CaO dispersion mixture is a promising treatment for the total immobilization of soil heavy metals As, Cd, Cr, Pb, and separation in dry conditions. Here, we studied the heavy metal immobilization by simple grinding with the addition of three mixtures: nano-Fe/CaO, nano-Fe/Ca/CaO, and nano-Fe/Ca/CaO/PO4. Samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) and scanning electron microscopy combined with electron dispersive spectroscopy (SEM–EDS). Results show that the addition of nano-Fe/Ca/CaO immobilized 95–99 % of heavy metals, versus 65–80 % by simple grinding. After treatment, 36–45 wt% of magnetic and 64–55 wt% of nonmagnetic fractions of soil were separated. Their condensed heavy metal concentration was 85–95 % and 10–20 %, respectively. Nano-Fe/Ca/CaO treatment reduced the concentration of leachates heavy metals to values lower than the Japan soil elution standard regulatory threshold of 0.01 mg/l for As, Cd, and Pb; and 0.05 mg/l for Cr. This technology can therefore immobilize totally soil heavy metals and reduce heavy metal by separation.  相似文献   

16.
Among the driving processes responsible for riparian forest dynamics the species-specific impact of flooding on the development of woody plants plays a key role—particularly for lowland rivers. Only a few of the forest succession models currently in use incorporate the flooding stress response of trees. This situation is mainly due to the incomplete investigation of the flooding tolerance processes and the related abiotic and biotic factors. In an attempt to use the wide-ranging but still rather vague knowledge available on flooding stress, the research presented in this paper proposes an approach to model tree response to flooding using the fuzzy set theory. The model is illustrated for the case of central European species. Flooding stress response to the abiotic factors of duration, depth and frequency of flooding differs according to five flooding tolerance classes and is expressed by means of a growth factor that limits optimal tree growth. We show that existing fuzzy set theory is able to generate and calibrate a flood stress response model which in turn can be incorporated into more complex forest succession models adapted to riparian areas.  相似文献   

17.
随着我国社会经济和城市化的快速发展,大气颗粒物是影响我国城市空气质量的首要污染物,大气细颗粒物污染已严重威胁我国居民健康。本文简要综述了PM2.5诱导的氧化应激和炎症反应在糖尿病的发生和发展中的分子作用机制。  相似文献   

18.
Genetic mechanisms of pollution resistance in a marine invertebrate.   总被引:1,自引:0,他引:1  
Pollution is a common stress in the marine environment and one of today's most powerful agents of selection, yet we have little understanding of how anthropogenic toxicants influence mechanisms of adaptation in marine populations. Due to their life history strategies, marine invertebrates are unable to avoid stress and must adapt to variable environments. We examined the genetic basis of pollution resistance across multiple environments using the marine invertebrate, Styela plicata. Gametes were crossed in a quantitative genetic breeding design to enable partitioning of additive genetic variance across a concentration gradient of a common marine pollutant, copper. Hatching success was scored as a measure of stress resistance in copper concentrations of 0, 75, 150, and 350 microg/L. There was a significant genotype x environment interaction in hatching success across copper concentrations. Further analysis using factor analytic modeling confirmed a significant dimension of across-environment genetic variation where the genetic basis of resistance to stress in the first three environments differed from that in the environment of highest copper concentration. A second genetic dimension further differentiated between the genetic basis of resistance to low and high stress environments. These results suggest that marine organisms use different genetic mechanisms to adapt to different levels of pollution and that the level of genetic variation to adapt to intense pollution stresses may be limited.  相似文献   

19.
Rorippa globosa has been identified as a newly-found Cd-hyperaccumulating species. In the present study, growth responses of Rorippa globosa and its accumulation characteristics of Cd and As were examined under joint stress of Cd and As. The results showed that Cd and As had an antagonistic effect on enhancing the growth of Rorippa globosa plants and Cd uptake and accumulation under the low concentration Cd and As treatments. When the concentration of Cd in the soil was 10 mg/kg and the concentration of As was 50 mg/kg, the highest growing height of the plant was up to 35.9 cm and the dry weight of the shoots was up to 2.2 g/pot, respectively. Meanwhile, the accumulation of Cd in the leaves under the joint stress was higher than that at the same level under single Cd pollution. However, there were synergic adverse effects on plant growth and Cd uptake under the combined pollution from a high concentration of Cd and As. Meanwhile, the accumulation of As in the roots was greater than that in the shoots, the translocation factor (TF) was ?0.3 and the bioaccumulation factor (BF) was ?0.6, thus showing that Rorippa globosa had an excluding effect on As uptake. These results confirmed that Rorippa globosa had a strong tolerant ability to the joint stress of Cd and As, and the potential for phytoremediation of soils contaminated by Cd and As.  相似文献   

20.
福寿螺是我国华南地区一种危害十分严重的外来入侵生物。采用分布广泛的四种植物:水蜈蚣(Kyllinga brevifolia Rottb.)、红花酢浆草(Oxalis corymbosa DC)、红叶乌桕(Euphorbia cotinifolia L.)和辣蓼草(Polygonum flaccidum Meissn.)作为原料,在实验室内通过人工研磨方法提取植物体内的有效成分作为药剂,分别对福寿螺幼螺进行室内毒杀及刺激其上爬的效果研究。结果表明:水蜈蚣提取物的杀螺效果不明显,而红花酢浆草、红叶乌桕、辣蓼草等三种植物提取物具有较好的杀螺效果。72h的毒性实验表明,这三种植物提取物在质量浓度为400mg·L-1时,均能全部杀死福寿螺幼螺;其中,红花酢浆草的杀螺效果最强,质量浓度为100mg·L-1时的杀螺率就达到80%,200mg·L-1的质量浓度下已能全部杀死福寿螺,红叶乌桕在200mg·L-1质量浓度时的杀螺率为56.67%,而在此质量浓度下辣蓼草仅为26.67%。另外,提取物刺激福寿螺上爬实验结果表明,红花酢浆草和红叶乌桕均有刺激福寿螺向上爬的作用,且红花酢浆草刺激作用稍强于红叶乌桕。综合杀螺和刺激福寿螺上爬作用的效果,可以得出在控制福寿螺上红花酢浆草和红叶乌桕是比较理想的备选植物。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号