聚硅氯化铝混凝剂的混凝效果研究

比较了聚硅氯化铝和聚合氯化铝处理各种地表水的混凝效果,结果表明,ＰＡＳＣ较ＰＡＣ具有更好的混凝效果。制备工艺和Ａｌ／Ｓｉ摩尔比对ＰＡＳＣ的混凝效果有影响,在相同Ａｌ／Ｓｉ摩尔比下,共聚法制备的ＰＡＳＣ的混凝效果优于复合法制备的ＰＡＳＣ。对ＰＡＳＣ而言在一定的Ａｌ／Ｓｉ摩尔比范围内其比值越小,混凝效果就越好。     

制备方法相同PAC的混凝效果评价指标

在无机高分子絮凝剂中 ,ＰＡＣ是研究最多、技术较成熟、性能较稳定而同时具有最大市场销售量的一种。为了定量地评价ＰＡＣ质量 ,一般以国家标准ＧＢ 15892— 1995为依据。其中盐基度 (Ｂ)是ＰＡＣ的重要质量指标 ,它直接决定着产品的化学结构形态和许多特性 ,如聚合度、分子电荷量、贮存稳定性、ｐＨ值、混凝能力等。因此Ｂ与ＰＡＣ的絮凝效能似乎有一定的关系 ,许多水处理厂的工作者试图寻找具有最佳混凝效果的Ｂ值。因为通过Ｂ值来判断ＰＡＣ的混凝效果是一条最简便的途径。Ｂ值是传统的羟基化的特征参数 ,它的计算公式为 :Ｂ =[ＯＨ]ａ…     

垃圾渗滤液的混凝--吸附预处理研究

研究表明,采用ＰＡＣ作混凝剂、焦炭作吸附剂,可有效去除渗滤液中的ＣＯＤ 和各部分重金属离子。ＰＡＣ和焦炭投量分别为４００ ｍｇ／Ｌ和８ ～１０ ｇ／Ｌ时,ＣＯＤ 去除率达５８ ．９ ％ ,重金属离子的去除率均达６０ ％ 左右,其中对Ｃｕ 的去除近１００ ％ ;混凝和吸附对各污染物的去除具有互补性,因而此工艺具有良好的运行灵活性和稳定性。混凝对渗滤液色度具有明显的去除效果（６８ ％ ） ;焦炭吸附中存在明显的竞争现象,其中对ＣＯＤ 的吸附具有明显的竞争优势     

垃圾渗滤液的混凝一吸附预处理研究

研究表明,采用ＰＡＣ作混凝剂,焦炭作吸附剂,可有效去除渗滤液中的ＣＯＤ和各部分重金属离子,ＰＡＣ和焦炭投量分别为４００ｍｇ／Ｌ和８～１０ｇ／Ｌ时,ＣＯＤ去除率达５８．９％,重金属离子的去除率均达６０％左右,其中对Ｃｕ的去除近１００％;混凝和吸附对各污染物的去除具有互补性,因而此工艺具有良好的运行灵活性和稳定性。混凝对渗滤液色度具有明显的去除效果（６８％）;焦炭吸附中存在明显的竞争现象,其中对ＣＯＤ     

适用于玻璃纤维增强水泥制品的低碱玻璃水泥

ＣａＯ－Ａｌ２Ｏ３系玻璃水泥是一种低碱水泥。纯ＣＡＳ玻璃相的水化产物主要为水化钙铝内长石晶体和ＣＳＨ凝胶，而掺与适量石膏的ＣＡＳ玻璃相的水化产物则为钙矾石晶体和ＣＳＨ凝胶，均具有较好的力学性能，石膏和氢氧化钙共同掺入则使ＣＡＳ玻璃相的胶凝性能恶化。ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２系玻璃水泥硬化浆体的ＰＨ值不超过１１。体积稳定性好，弹性模量低，容量小，特别适用于制作轻质薄壁的玻璃纤维增强水泥制品。     

添加物对LF炉用镁钙碳砖性能的影响

分析了Ａｌ、Ｓｉ添加物不能增强镁钙碳砖并使碳化后制品膨胀的原因。试验结果显示：Ａｌ和Ｓｉ在高温下氧化成Ａｌ２Ｏ３和ＳｉＯ２，给而再与ＣａＯ反应，生成Ｃ３Ａ和Ｃ２Ｓ，再加上Ｃ２Ｓ的晶型转变，这一系列反映一方面使Ａｌ３Ｃ４和ＳｉＣ的生成最减少，另一方面产生很大的体积膨胀效应，导致产品结构破坏，因此，与镁碳砖不同，Ａｌ和Ｓｉ对镁钙碳砖没有增强作用。     

新型无机絮凝剂——聚合氯化硫酸铁铝(PAFCS)

新型无机絮凝剂——聚合氯化硫酸铁铝（ＰＡＦＣＳ）ＰＡＦＣＳ不但具有聚合铝的优良混凝性能和聚合铁的强吸附性、快速沉淀及适用范围宽等特性，而且原料易得，成本低、更加经济实用。更重要的是投药所带入的杂质和处理后留下的铝大大减少，这对饮用水水质的提高，保证人...     

混凝剂中的铝形态对藻类混凝过程的影响

为了考察混凝剂中的铝形态对藻类混凝过程的影响,使用3种具有不同铝形态分布的混凝剂对含藻水进行了混凝试验。结果表明,硫酸铝由于具有较低含量的Alb,电中和能力较差,故需要较大的投量才能去除藻类,形成絮体;含藻水体系中的有机物主要是腐殖酸及富里酸类物质,微生物代谢产物(SMP)在硫酸铝作混凝剂时得到较好的去除,而腐殖酸及富里酸的去除率较低可能是造成硫酸铝混凝效果较差的原因;Alc(Al(30))在混凝中的作用机理主要是吸附架桥作用,可有效去除水体中的有机物,Al₁₃的主要作用机理是电中和作用,可以有效去除水体中的颗粒物;Al₁₃与Al₃₀由于具有形态的稳定性,其混凝过程受pH值的影响较小。絮体强度因子随着pH值的升高先增大后减小,Al₁₃作混凝剂时絮体恢复因子随pH值的升高先增大后减小,而其他两种混凝剂所形成絮体的恢复因子随pH值的升高而增大。     

BACnet/IP:BACnet的互联网扩展(下)──BACnet协议标准技术系列讲座(7)

３ ＢＡＣｎｅｔ／ｉＰ网络 附件 Ｈ的 ＰＡＤ设备是实现在 ＩＰ网络上互连ＢＡＣｎｅｔ网络的最简单的方法，但是，这种方法有一些不足。其中之一是，不容易从网络中增删设备。如果要重构网络时，必须重新改写每一个ＰＡＤ中的对等ＰＡＤ设备表。为此，ＳＳＰＣ１３５开发了一个更有效的协议，称为ＢＡＣｎｅｔ／ＩＰ，作为附件Ｊ加入到ＢＡＣｎｅｔ标准中。ＡＳＨＲＡＥ于１９９９年１月正式发布附件Ｊ作为ＢＡＣｎｅｔ标准的附件，成为美国国家标准。附件Ｊ详细规范了使用ＴＣＰ／ＩＰ协议通信的设备组建ＢＡＣｎｅｔ网络的技术，并且将…     

聚硅酸聚合硫酸铁的研究

以硅酸钠、硫酸和聚合硫酸铁（简称ＰＦＳ）为原料制备聚合硅酸硫酸铁（简称ＰＳＰＦＳ）测定了ＰＳＰＦＳ红外光谱,研究了Ｆｅ／Ｓｉ摩尔比和水样ＰＨ值等因素对产品性能和除浊效果的影响,当Ｆｅ／Ｓｉ摩尔比为１．５时产品稳定性和除浊效果均较好。     

聚合硅酸铝铁混凝处理水中残余铝含量的研究

通过一系列生产实验,探讨了PAFSC的碱化度和Al/Fe/Si摩尔比以及水样pH值,水温对水中残余铝含量的影响,结果表明,用PAFSC处理后的水样具有更低的残余铝含量,残余铝随水温升高呈增加趋势,最佳pH值随水温的增加而降低。     

Evaluation of aluminum-silicate polymer composite as a coagulant for water treatment

Aluminum-silicate polymer composite (PASiC), a new kind of inorganic coagulant, was produced by two approaches: (1) hydroxylation of the mixture of AlCl3 and fresh polysilicate (PASiCc); (2) hydroxylated polyaluminum-chloride (PAC) combined with fresh polysilicate (PASiCm). The PASiC products had the following properties: Al2O3 content = 6.40-7.30%, SiO2 content = 0.40-0.82%, Al/Si ratios = 10-20, basicity (OH/Al molar ratio, denoted B) = 1.2-2.0. The coagulation behaviour of PASiC and PAC under conditions typical for coagulation and flocculation in water treatment were investigated by studying the rate of floc size development, the variety of streaming current value, the efficiency of turbidity removal and the effect of pH on the turbidity removal efficiency, and the stability of PASiC. The results detailed in this study suggest that, compared with PAC, PASiC may enhance aggregating efficiency and give better coagulating effects, but weaken charge effectiveness in coagulation process or become unstable when stored for longer time, especially at higher B value and lower Al/Si ratio. The coagulating effect of PASiC is closely linked to the preparation procedure. With the increase of B value and the decrease of Al/Si ratio, the coagulation efficiency of PASiC increases, and at the same B value and Al/Si ratio, PASiCc seems to give a little better coagulation effect than PASiCm but less stability. The Al/Si ratio should not be too low or the B value should not be too high, otherwise, the PASiC products tend to become cloudy or partly gelatinous, which will make them loss some coagulation efficiency.     

Effect of citric acid on aluminum hydrolytic speciation

The mechanisms of the influence of organics on Al transformation were not fully understood. This study investigated the effect of citric acid on Al speciation in partially neutralized aluminum solution. The partially neutralized solution was prepared with 20 mmol L(-1) AlCl3 without citrate (citrate/Al molar ratio of 0, control) or with citrate (citrate to Al molar ratios between 0.1 and 3.0) at pH between 3.0 and 7.0. The nature of aluminum hydrolytic products as influenced by citrate complexation was investigated by turbidity measurement, ferron kinetic color development, peak line width in 27Al nuclear magnetic resonance (NMR) deconvolution demodule quantitative methods, and the MinteqA2 chemical speciation program. Sulfate precipitates from Al solution as influenced by citrate were examined by X-ray diffraction (XRD) analysis and atomic force microscopy (AFM). The turbidity of the Al solution increased with increasing pH values. Increases in citrate/Al molar ratio from 0 to 0.1 decreased dramatically the turbidity due to citrate complexation. The 27Al NMR peak at 6 ppm of the Al solution at a citrate/Al molar ratio of 0.5 shifted to 8 and 10 ppm in the solutions at citrate/Al molar ratio of 1.0 and 3.0, respectively. Comparison of 27Al NMR data and the data obtained from the MinteqA2 chemical speciation program, indicate that the Al-citrate complexes as revealed by 27Al NMR data are largely Al(citrate), AlH(citrate)+, and Al(citrate)(2)3- complexes (99-112%) in the pH range of 4.5-6.5. The non-detected Al fractions by the MinteqA2 program account for 82-99% of the non-detected Al fractions by NMR quantitation in the same pH range. The AFM of sulfate precipitates from solutions with low citrate/Al molar ratios (i.e., 0.01, pH 4.5, aged 40 days) shows that Al13 sulfate precipitates were ellipse-shaped. These ellipse-shaped precipitates were aggregated when solution pH increased from 4.5 to 7.0 (aged 40 days), indicating the fast hydrolytic rate of Al at high pH. The sulfate precipitates from solution with a high citrate/Al molar ratio (i.e., 0.05, pH 4.5, aged 40 days) also shows aggregate of particles, and XRD non-crystallized precipitates the hampering effect of citrate on Al precipitates.     

常规处理工艺中铝含量变化的影响因素与控制方法

通过烧杯试验及现场中试,研究了聚合氯化铝投加量和PH对常规处理工艺中过程水和滤后水余铝含量的影响.结果表明,在水厂实际生产中,应保证混凝反应出水pH≤7.6,以降低过程水的余铝含量;若反应后水pH>7.8,则出厂水铝含量极易超标.     

Use of synthetic zeolites for arsenate removal from pollutant water

Arsenic is known to be a hazardous contaminant in drinking water that causes arsenical dermatitis and skin cancer. In the present work, the potential use of a variety of synthetic zeolites for removal of arsenic from water below the current and proposed EPA MCL has been examined at room temperature. Experiments have been conducted to examine the extent of arsenic removal as a function of pH. The effect of initial arsenic concentration and liquid to solid ratio in the batch reactions has also been studied. Zeolite NH4+/Y (NY6) showed significant arsenate removal capacity over a wide initial pH range of 2-12. Zeolite NY6 achieved this performance by buffering the initial pH to within a range of 3.5 < pH < 7 where uptake of arsenate onto aluminol surface groups is at a maximum. The high aluminum content of NY6 (i.e. low Si/Al ratio) was an important factor governing the improved performance of this zeolite relative to other tested zeolites with higher Si/Al ratio. The pH buffering capacity of NY6 could lead to savings in cost and process time for industrial effluent treatment due to avoidance of a pH pre-conditioning step prior to arsenate removal.     

矿井水处理聚合氯化铝残留物对超滤膜污染的影响

针对矿井水混凝处理过程中投加的聚合氯化铝(PAC)残留物对超滤膜的污堵问题,采用在聚偏氟乙烯(PVDF)超滤膜前投加不同量的PAC对矿井水进行混凝和超滤试验,考察PAC不同投加量下浊度、污染指数(SDI)、残留铝含量、跨膜压差(TMP)和归一化膜比通量(NSF)间的相互关系及对超滤膜的影响。结果表明:当PAC投加量为35~40 mg/L时,混凝上清液中SDI最小为5. 3,残留铝含量约为0. 16~0. 23 mg/L,浊度约为6. 0~8. 0 NTU。跨膜压差随着PAC投加量、残留铝含量和pH值的增加而上升。当PAC投加量为40 mg/L、残留铝含量为0. 18 mg/L、pH值为4. 2~5. 2时,跨膜压差(TMP)最小值约为64. 8~68. 4 kPa。水中残留铝存在形态在不同pH值条件下可相互转化,其聚合态和絮凝体粒径又影响着超滤膜污染,酸性条件(pH值为4. 2~5. 2)下更有助于减少残留铝对超滤膜的污染。     

复合混凝剂PTA-CPAM的形貌结构与净水性能

以聚合氯化铝(PAC)、四氯化钛(TiCl_4)、阳离子聚丙烯酰胺(CPAM)为原料成功制备无机-有机复合混凝剂聚钛氯化铝-阳离子聚丙烯酰胺(PTA-CPAM),采用红外光谱(IR)、扫描电镜(SEM)、能谱分析(EDS)与差热热重(TG-DTA)对产物的结构、组成及热稳定性进行分析。此外,对PTA-CPAM的混凝性能进行研究。结果表明:当m(CPAM)/m(PTA)=0.4、PTA-CPAM投加量为9.0mg/L、pH为9.0的条件下,混凝剂的净水效果最优,且PTA-CPAM对不同初始浊度的水样都有较优的除浊能力;协同增效作用使PTA-CPAM具备更强的吸附电中和与吸附架桥网捕能力,表现出优异的除浊性能。     

梅子青青釉的研制

采用龙泉当地原料西源与黄坛,配合石英、方解石、滑石、氧化铬等原料制备青釉。实验采用单因素实验法,在1280℃～1320℃还原气氛烧成下获得了釉面效果较好的梅子青青釉。考察了西源含量、氧化铬含量、Si/Al摩尔比和釉层厚度等因素对青釉呈色的影响。研究结果表明：当配方组成：西源22%、Si/Al摩尔比9.5、方解石17%时,控制釉层厚度为1.5 mm,获得的梅子青青釉釉面效果最好。     

Hexavalent chromium removal from aqueous solution by adsorption on aluminum magnesium mixed hydroxide

A series of sols consisting of aluminum magnesium mixed hydroxide (AMH) nanoparticles with various Mg/Al molar ratios were prepared by coprecipitation. The use of AMH as adsorbent to remove Cr(VI) from aqueous solution was investigated. Adsorption experiments were carried out as a function of the Mg/Al molar ratio, pH, contact time, concentration of Cr(VI) and temperature. It was found that AMH with Mg/Al molar ratio 3 has the largest adsorption efficiency due to the smallest average particle diameter and the highest zeta potential; AMH was particularly effective for the Cr(VI) removal in a pH range from acid to slightly alkaline, even though the most effective pH range was between 2.5 and 5.0. The adsorption of Cr(VI) on AMH reached equilibrium within 150 min. The saturated adsorption capacities of AMH for Cr(VI) were 105.3-112.0 mg/g at 20-40 °C. The interaction between the surface sites of AMH and the Cr(VI) ions may be a combination of both anion exchange and surface complexation. The pseudo-second-order model best described the adsorption kinetics of Cr(VI) onto AMH. The results showed that AMH can be used as a new adsorbent for Cr(VI) removal which has higher adsorption capacity and faster adsorption rate at pH values close to that at which pollutants are usually found in the environment.