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本文对影响含活性硅酸碱式氯化铝铁(PAFCS)净水剂混凝去浊效果的有关主要因素进行了考察研究,确定了PAFCS净水剂具有较佳混凝去浊效果的Si:Al:Fe摩尔比和OH/(Al Fe)摩尔比以及较佳投药量范围;考察了PAFCS对水质变化的适应性;并与常用净水剂进行了混凝去浊效果的对比试验。 相似文献
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采用自行制备的具有不同SiO2 :Al:Fe(摩尔比值 )和碱化度的两类新型无机高分子混凝剂聚硅酸氯化铝铁 (PSAFC)和聚硅酸硫酸铝铁 (PSAFS)各 7种 ,直接对印染废水进行处理。从中选出 2种混凝剂 ,考察了pH值、混凝剂投量等对混凝效果的影响 ,并对混凝处理后 ,印染废水出水中残留混凝剂主要成分Al、Fe、SiO2 的含量进行分析。实验结果表明 ,氯化物型 (PSAFC)和硫酸盐型 (PSAFS)混凝剂对印染废水的色度、浊度、CODCr均有良好的去除效果 ;总体而言 ,PSAFS的混凝效果略优于PSAFC ;混凝处理后印染废水出水中残留铝、铁、硅的含量均比较低 ;pH值和碱化度对混凝剂在水体中残留铝含量有影响 相似文献
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为提高铝基复合混凝剂的混凝效果,以AlCl3、MgCl2、TiCl4为原料,通过共聚反应制备出无机复合高分子混凝剂PCAMT(聚合氯化铝镁钛),并探究其混凝机理.采用Ferron(高铁试剂)逐时络合比色法、红外光谱、X-射线衍射谱图、扫描电镜与能谱分析(SEM-EDS)、Zeta电位对产物的Al形态、结构形貌、组成及混凝机理进行分析.结果表明:①采用单因素试验法获得最佳合成条件,即反应温度为60 ℃,Mg/Al(摩尔比,下同)为0.5,Ti/Al(摩尔比,下同)为0.5,OH/(Al+Mg+Ti)(摩尔比,下同)为0.6.②形态分析表明,反应温度、Mg/Al、Ti/Al,OH/(Al+Mg+Ti)对Al的形态分布均存在影响.随着反应温度的升高,n(Ala)(Ala在Al的水解聚合形态中所占摩尔分数,下同)先减后增,n(Alb)(Alb在Al的水解聚合形态中所占摩尔分数,下同)先增后减,n(Alc)(Alc在Al的水解聚合形态中所占摩尔分数,下同)逐渐减小;随着Mg/Al的增大,n(Ala)先减后增,n(Alb)、n(Alc)为先增后减的趋势;随着Ti/Al的增大,n(Ala)逐渐增加,n(Alb)逐渐减少,n(Alc)先增后减;随着OH/(Al+Mg+Ti)的增大,n(Ala)逐渐减少,n(Alb)、n(Alc)逐渐增加.③通过红外光谱、X-射线衍射,确定了PCAMT的结构组成,表明PCAMT是一种—OH桥联的铝镁钛复杂无定型聚合物,含有Al—OH—Mg与Ti—O—Ti新基团以及形成了Mg1.5Ti1.25O4、Mg1.2Ti1.8O5、Al3Ti5O2等共聚物.④扫描电镜与能谱结果表明,PCAMT呈紧凑的空间立体网状形貌结构,利于发挥吸附架桥、网捕卷扫作用.⑤由PCAMT投加量对Zeta电位的影响分析可知,低投药量的混凝过程中起主导作用的是电中和作用,高投药量PCAMT处理原水的混凝机制以吸附架桥和网捕卷扫作用为主.研究显示,AlCl3、MgCl2和TiCl4通过共聚反应,可生成具有更高聚合度的无定型共聚物PCAMT,利于电中和、吸附架桥和网捕卷扫,具有较好的混凝效果. 相似文献
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Jianqiang Wang Meiqing Shen Jun Wang Mingshan Cui Jidong Gao Jie M Shuangxi Liu 《环境科学学报(英文版)》2012,24(4):757-764
FeOx-CeO2 mixed oxides with increasing Fe/(Ce+Fe) atomic ratio (1-20 mol%) were prepared by sol-gel method and characterized by X-ray powder diffraction (XRD), Brunauer-Emmett-Teller (BET) and Hydrogen temperature-programmed reduction (H2-TPR) techniques. The dynamic oxygen storage capacity (DOSC) was investigated by mass spectrometry with CO/O2 transient pulses. The powder XRD data following Rietveld refinement revealed that the solubility limit of iron oxides in the CeO2 was 5 mol% based on Fe/(Ce+Fe). The lattice parameters experienced a decrease followed by an increase due to the influence of the maximum solubility limit of iron oxides in the CeO2. TPR analysis revealed that Fe introduction into ceria strongly modified the textual and structural properties, which influenced the oxygen handling properties. DOSC results revealed that Ce-based materials containing Fe oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicated that the calculated apparent kinetic parameters obey the compensation effect. The three-way catalytic performance for Pd-only catalysts based on the Fe doping support exhibited the redundant iron species separated out of the CeO2 and interacted with the ceria and Pd species on the surface, which seriously influenced the catalytic properties, especially after hydrothermal aging treatment. 相似文献
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The aim of the present work was to produce a polyaluminium ferric silicate chloride (PAFSiC) coagulant from acidic and alkaline
wastewater of purifying graphite by roasting, and subsequently to evaluate coagulation efficiency of the reagent by treating surface
water from the Yellow River as well as municipal wastewater in comparison with the conventional coagulant polyaluminium chloride
(PAC). The PAFSiC coagulant was prepared by co-polymerization. The effects of (Al+Fe)/Si molar ratio, OH/(Al+Fe) molar ratio (i.e.,
value), coagulant dosage and pH value of test suspension on the coagulation behavior of FAFSiC and the stability of the PAFSiC were
also examined. Results showed that PAFSiC performed more efficiently than PAC in removing turbidity, chemical oxygen demand
(COD), and total phosphate (TP). The PAFSiC with a
value of 2.0 and (Al+Fe)/Si ratio of 5 (PAFSiC 2.0/5) showed excellent
coagulation effect for both turbidity and COD, while PAFSiC 1.0/5 was the best for TP. The optimum coagulation pH range of PAFSiC
2.0/5 was 5.0–9.0, slightly wider than that of PAC (6.0–8.0). The process can be easily incorporated into high-purity graphite production
plants, thereby reducing wastewater pollution and producing a valuable coagulant. 相似文献
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We used toxicity identification evaluation (TIE) method to confirm the combinational e ects of identified toxic metals in a paper
recycling mill e uent in inducing the decreased lifespan in nematode Caenorhabditis elegans. Exposure to Ca + Al caused more
severely decreased lifespan than that exposed to Ca, or Al; and exposure to Ca + Fe induced more severely decreased lifespan than that
exposed to Ca, or Fe. Exposure to Ca+Al+Fe caused more severely decreased lifespan than that exposed to Ca, or Ca+Fe. Moreover,
the baseline toxicity on lifespan was doubled by doubling the concentration of combined metals (Ca+Al+Fe) in spiking test in original
e uent (oe), and lifespan defects in oe+Ca+Al+Fe exposed nematodes were more severe than that in Ca+Al+Fe exposed nematode.
Therefore, Ca+Al+Fe exposure may largely explain the formation of decreased lifespan induced by the examined industrial e uent.
Furthermore, the observed reduction of lifespan induced by the combination of high level of Ca with other metals may be at least
partially independent of the insulin-like pathway. 相似文献
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土壤中铁铝氧化物在团聚体稳定性和有机碳吸附方面具有重要作用,而氮添加对土壤氮循环影响的变化也可能与其有关,但是目前尚缺乏在氮循环方面的研究.为了探究铁铝氧化物在土壤氮素转化中的作用,选择福建省建瓯罗浮栲森林土壤为研究对象,采用选择性溶提技术准备不同的土壤——未经处理(T1)的土壤和去除游离态铁铝氧化物(T2)土壤、去除非晶质铁铝氧化物(T3)土壤、去除络合态铁铝氧化物(T4)土壤,在这些土壤中添加不同形态氮(40 mg/kg)——丙氨酸(氨基酸态氮,AA)、硫酸铵(铵态氮,AN)、硝酸钠(硝态氮,NAN)和亚硝酸钠(亚硝态氮,NIN),进行室内培养试验,分析氮含量变化和氮素转化情况.结果表明:①与CK处理相比,AA和AN处理均增加了T1土壤中w(NH4+-N),NAN处理增加了w(NO3--N),但低于添加量,表明添加氨基酸和铵态氮均会促进氮矿化,添加硝态氮会增加NO3--N的固定且抑制其硝化.②在CK处理下,与T1土壤相比,T2和T4土壤中w(NH4+-N)、w(NO3--N)和w(氨基酸)均降低,但T3土壤中w(NH4+-N)和w(氨基酸)增加、w(NO3--N)降低,表明土壤中游离态氧化铁铝和络合态氧化铁铝的存在有助于氮素矿化,非晶质氧化铁铝有助于硝化.③在不同氮处理下,各土壤的氮含量及其转化速率与CK处理规律相似.与CK处理相比,各氮处理均未显著增加T2和T4土壤中w(NH4+-N),且AA和AN处理均未影响T2、T3和T4土壤中w(NO3--N)和w(氨基酸).结果显示,氮添加并没有改变铁铝氧化物的作用,其中,矿化和氨化作用均表现为游离氧化铁铝>络合氧化铁铝>非晶质氧化铁铝,硝化作用表现为非晶质氧化铁铝>游离氧化铁铝>络合态氧化铁铝.因此,土壤铁铝氧化物的不同存在状态应该是调节氮素转化的重要土壤条件. 相似文献
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为了解三七中Fe、Mn、Al、Zn、Se人体微量元素的含量,并客观评价这5种微量元素对长期服用三七药品的患者的健康风险,在三七的产区及周边市县进行采样,采用电感耦合等离子体质谱仪(ICP-MS)对三七中这5种微量元素的含量进行测定,并采用点推定和概率推定对各元素的非致癌风险危害商值(HQ)值进行评估,结果发现三七中5种微量元素的平均含量分别为1375.84,108.31,1213.62, 0.16,21.99mg/kg,表现出Al > Fe > Mn > Zn > Se的高低顺序,HQ值大小顺序为Fe > Al > Mn > Zn > Se. HQ值均小于1,提示针对各元素,一般消费者不存在非致癌健康风险.然而,Fe,Al,Mn的日摄入量分别为0.09573,0.10759,0.00832mg/(kg·d),超出了来源于药物的微量元素的经口允许摄入量,应该加以控制.对危害指数(HI)的概率推定结果显示,5.19%的三七服用者对这5种微量元素的暴露具有非致癌健康风险. 相似文献
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Species distribution of polymeric aluminium-ferrum--timed complexation colorimetric analysis method of Al-Fe-ferron. 总被引:2,自引:0,他引:2
The effects of the colorimetric buffer solutions were investigated while the two colorimetric reactions of Al-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and the pH of the solutions were also investigated. A timed complexation colorimetric analysis method of Al-Fe-ferron in view of the total concentration of (Al + Fe) was then established to determine the species distribution of polymeric Al-Fe. The testing wavelength was recommended at 362 nm and the testing pH value was 5. With a comparison of the ratios of nAl/nFe, the standard adsorption curves of the polymeric Al-Fe solutions were derived from the experimental results. Furthermore, the solutions' composition were various in both the molar nAl/nFe ratios, i.e. 0/0, 5/5, 9/1 and 0/10, and the concentrations associated with the total [Al + Fe] which ranged from 10(-5) to 10(-4) mol/L. 相似文献
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以溶胶-凝胶法制备纯的和分别掺杂Fe3+、Ce3+的TiO2纳米粒子,以橙黄IV的光催化氧化评价纳米粒子的紫外光与可见光活性,利用TG-DSC、XRD、BET及UV-Vis吸收光谱考察掺杂对TiO2的相变、粒径、比表面积及光吸收性能的影响,在归一化条件下探讨Fe3+及Ce3+掺杂对TiO2活性和表面性质产生影响的机制。结果表明:Fe3+及Ce3+的最佳掺杂量分别为0.2%和0.04%;Ce3+抑制TiO2由锐钛矿向金红石转变以及改善TiO2高温组织稳定性的能力均明显大于Fe3+;Fe3+和Ce3+掺杂均能提高TiO2的紫外光活性并扩展TiO2的光响应范围,但光生电子与空穴复合以及光腐蚀使它们对TiO2可见光活性的提高并不显著。Fe3+和Ce3+的半径及其相应氧化物的性质决定了两者对TiO2性能的不同影响。 相似文献
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为了探讨慢性铝暴露对大鼠铁代谢的影响,将100只4周龄清洁级雄性Wistar大鼠随机均分成摄铝组(430mg·L-1,以Al3+计)与对照组(蒸馏水),饮水染铝,每隔30d处死染铝大鼠和对照大鼠各10只,实验周期为150d.同时,在不同时间点(30d、60d、90d、120d、150d)测量大鼠体重,并进行协方差分析.最后,用火焰原子吸收分光光度法、固相竞争ELISA和比色法检测血浆Al、Fe、转铁蛋白(TF)、可溶性转铁蛋白受体(sTfR)含量及总铁结合力(TIBC).结果表明,在摄铝前期(90d前),染铝对大鼠体重无显著影响,而后期(120d后)染铝对大鼠体重抑制作用较大.在实验周期内,各时间点间对照组血浆中各指标均无显著差异,摄铝组随着时间的延长各指标变化较大.各时间点摄铝组血浆中Al含量及Al/Fe均显著高于对照组(p0.01);30d时摄铝组血浆中Fe含量与对照组相比无显著差异(p0.05),60、90、120d时均显著低于对照组(p0.01),150d时显著高于对照组(p0.01);30、60d时摄铝组血浆TF含量与对照组相比无显著差异(p0.05),90d后显著高于对照组(p0.05;p0.01);30、60d时摄铝组TIBC与对照组相比无显著差异(p0.05),其后各时间点均显著高于对照组(p0.01);30d时摄铝组sTfR含量与对照组相比无显著差异(p0.05),其后各时间点均显著低于对照组(p0.01).由此可见,铝可干扰大鼠体内铁的代谢,影响铁的生物学作用. 相似文献