Effect of Al(III) speciation on coagulation of highly turbid water

In Taiwan, the turbidity of raw water for fresh water treatments can sometimes reach as high as 40 000 NTU due to intensive rainfall, especially in typhoon seasons. In response, water works often apply large quantities of coagulants such as polyaluminium chloride (PACl). In this study, simulated and natural highly turbid water was coagulated with two PACls, a commercial product (PACl-1) and a laboratory product (PACl-E). The Al species distributions of PACl-1 and PACl-E under various pH conditions were determined, and the corresponding coagulation efficiency was evaluated. The PACl-E has a wider range of operational pH, while the efficiency of PACl-1 peaks at around neutral pH. For simulated water up to 5000 NTU, the PACl-E was superior to PACl-1 at low dosage and in the pH range studied. Similar results were discovered with natural water, except that when the turbidity was extremely high, the coagulation efficiency of PACl-E decreased significantly due to the presence of large amounts of organic matter. The coagulation of PACl-E was closely related to the content of polycationic aluminium (Al₁₃) while that of PACl-1 was dictated by the amount of Al_c. The sludge from PACl-E coagulation had better dewaterability when the optimum dosage was applied. The experimental results suggest that for natural water up to 5000 NTU, PACl containing high Al₁₃ species is recommended for coagulation. In cases when the water contains high organic matter, efficient coagulation depends upon enmeshment by amorphous aluminium hydroxide.     

聚丙烯酸水凝胶对氯化-1-丁基-3-甲基咪唑离子液体的吸附热力学和动力学研究

通过水溶液聚合法制备了聚丙烯酸水凝胶（polyacrylic acid,PAA）,研究了溶液酸碱度和温度对聚丙烯酸水凝胶吸附氯化1-丁基3-甲基咪唑离子液体的影响。结果表明,水凝胶对氯化1-丁基3-甲基咪唑离子液体的吸附量随溶液pH值增大而逐渐增大,pH=2～4时增幅明显,而pH大于4时变化趋于缓慢;随温度的升高而逐渐降低。该等温吸附行为基本符合Langmuir吸附等温式,由二级吸附动力学模型获得的吸附过程活化能（Ea=52.470 kJ/mol）可以看出,PAA对氯化1-丁基3-甲基咪唑的吸附属于化学吸附范畴。     

不同氯离子浓度对电化学法处理微污染水中含氮化合物的影响

采用电化学氧化法对微污染水进行处理,在极板间距为1 cm,电解时间为10 min的条件下,通过投加NaCl溶液,使水中的NH4+及Cl-的摩尔比分别为1∶1、1∶2、1∶3,并与未投加NaCl溶液的电解出水进行比较,主要考察不同氯离子浓度对电化学法去除微污染水中的含氮化合物的效果影响.实验表明:随着氯离子浓度的不断提高...     

复合絮凝剂APAC中铝形态分布及絮凝性能研究

用慢速滴碱法合成聚合氯化铝的过程中加入酸改性的凹凸棒,制备了新型絮凝剂APAC。采用Al-Ferron逐时络合比色法和烧杯絮凝实验法分别研究了APAC复合絮凝剂中铝的形态分布和絮凝性能。结果表明,Ala随盐基度的升高而逐渐降低;Alb随盐基度的升高而升高;Alc则先随盐基度的升高而升高,达到最大值后,再随盐基度的升高而降低。在相同实验条件下,盐基度愈高,混凝效果愈好,Alb含量愈高,混凝效果并不一定愈好。因此,APAC的质量控制以及追求目标应当是尽量提高Alc的含量,而不是Alb的含量。     

循环流化床灰制备聚合氯化铝铁絮凝剂

以煤矸石电厂循环流化床灰(CFB灰)为原料,采用酸浸、水解、聚合和熟化等工艺过程,制备聚合氯化铝铁(PAFC)絮凝剂产品。重点对制备PAFC絮凝剂的酸浸工艺参数进行研究,其最佳工艺条件为:盐酸浓度为20.2%、酸浸温度为110℃、酸浸时间为2 h、液固比为4∶1;Fe2O3浸出率为90.6%,Al2O3的浸出率为48.5%。同时采用实验得出的最优工艺参数进行了产品制备,并对产品进行了絮凝性能实验。结果表明,在相同条件下PAFC的絮凝效果明显好于聚合氯化铝(PAC),用CFB灰制备PAFC絮凝剂产品是可行的。     

Effects of copper chloride on formation of polychlorinated dibenzo-p-dioxins in model waste incineration

Combustion experiments in a laboratory-scale fluidized-bed reactor were conducted to elucidate the effects of copper chloride as a catalyst on polychlorinated dibenzo-p-dioxins (PCDDs) formation in municipal waste incineration. We used model wastes with and without copper chloride (CuCl₂ · 2H₂O), both of which contained polyvinyl chloride as a chlorine source. Combustion temperature was set to 900 °C, and the amount of air supplied was twice the stoichiometric ratio. The experimental setup was carefully planned to suppress the influences of experimental conditions except the waste composition. Results of these experiments showed that copper chloride in the waste increased the amount of PCDDs formed and made the homologue profile to shift towards the highly chlorinated species. Copper chloride contributes to the PCDDs formation by promoting chlorination, whereby the reaction is important in that organic matter is chlorinated directly by copper compounds. Copper chloride did not exert a great influence on the isomer distribution patterns of PCDDs, while there appeared a significant difference in the case of PCDFs. This points out the difference of the major formation mechanisms between PCDDs and PCDFs. PCDDs are less formed by the catalytic reactions from carbon/polycyclic aromatic hydrocarbons than PCDFs in our experimental conditions.     

表面活性剂底喷填料塔的氯化铵微粒脱除增效作用

为高效去除微细颗粒物和减少水雾排放,设计了一种底喷式填料塔,利用表面活性剂能降低水的表面张力的原理,对比分析饮用水、SDBS、AEO-9、A-7对粒径小于1 μm的氯化铵微粒的净化效果。结果表明,当底喷填料塔入口氯化铵微粒质量浓度为124.9~194.3 mg·m⁻³时,饮用水洗涤液的微粒脱除效率仅在40%左右,出口氯化铵微粒质量浓度>70 mg·m⁻³;当采用SDBS和AEO-9表面活性剂洗涤液后,微粒脱除效率大幅提高。AEO-9的提效作用较明显,当AEO-9浓度增至0.004%时,脱除效率达到74.8%,氯化铵微粒出口浓度为26.5 mg·m⁻³;当采用浓度为0.3%的A-7洗涤液时,脱除效率为89%,此时氯化铵微粒出口浓度仅为15 mg·m⁻³。通过分析可知,表面活性剂洗涤液对微细颗粒物的脱除有提效作用。     

循环流化床灰制备聚合双酸铝铁絮凝剂

为了提高循环流化床灰(CFB灰)的资源综合利用率对CFB灰制备聚合双酸铝铁(PAFCS)的可行性及工艺参数进行了研究,提出了以酸浸、水解、聚合和熟化等工艺过程,制备PAFCS混凝剂产品。重点对制备PAFCS絮凝剂的工艺参数进行研究,并利用红外光谱分析技术对PAFCS进行了结构表征及实验了PAFCS絮凝性能。结果表明,在相同条件下PAFCS的絮凝效果明显好于聚合氯化铝(PAC),用CFB灰制备PAFCS絮凝剂产品是可行的。     

氯化钙控制污泥膨胀

污泥膨胀是活性污泥工艺运行中经常遇到的最棘手的问题之一。本实验以人工合成污水为底物,采用序机式活性污泥法（SBR）;研究投加无机混凝剂氯化钙控制污泥膨胀的情况,同时研究丝状菌和菌胶团的变化。研究发现,投加氯化钙后,丝状菌数量明显减少;形成较多大而密实规则的菌胶团,污泥膨胀得到控制。污泥容积指数（SVI）由最初的309.5 mL/g降到67.1 mL/g,污泥沉降性能改善。停止投加氯化钙后又运行了18周期,活性污泥没有发生再次膨胀。投加氯化钙对COD去除率没有明显影响。研究结果表明,投加氯化钙是一种有效的污泥膨胀应急控制措施。     

聚硅酸氯化铝铁絮凝剂制备及絮凝效果的研究

以粉煤灰和硫铁矿烧渣两种工业固体废弃物为主要原料,制取聚硅酸氯化铝铁(PSAFC)无机高分子絮凝剂。粉煤灰、硫铁矿烧渣和纯碱按1：1：0．8混合．在800～900(焙烧15～30min,用定量1：1盐酸浸取,固体溶出率高达94％,陈化后即为PSAFC絮凝剂。通过模拟和真实印染废水絮凝试验．表明PSAFC絮凝效果与聚合氯化铝(PAC)相当,在沉降速度、污泥体积等方面要优于PAC,且成本比PAC低．具有较大的市场前景。