高岭土对氢氧化镁混凝去除活性橙染料效果的影响

实际染料废水存在一定浊度,本文将高岭土和活性橙染料模拟配水混合,讨论不同镁盐混凝剂投加量的混凝效果和絮体特性;同时,讨论高岭土浓度对混凝的影响。研究结果表明:在镁盐投加量(以Mg2+计)为150mg/L时,混合高岭土的混合配水活性橙染料和浊度的去除效果好于未混合高岭土的配水,说明混凝过程中高岭土的存在能够对颗粒分离和活性染料去除起到显著提升作用;根据絮凝指数FI值和沉降后水样zeta电位的变化情况,可以得出镁盐混凝机理主要是网捕卷扫和电性中和共同作用;混凝絮体显微照片中絮体特征进一步证实了镁盐混凝剂对不同浊度高岭土-活性橙染料混合配水的混凝效果。实验得出高岭土-活性橙染料混合配水最佳镁投加量150mg/L,最佳高岭土浓度10mg/L。     

混凝与光催化联用处理水体中的复合染料

利用混凝与光催化处理酸性橙Ⅱ染料水样、碱性嫩黄O染料水样以及酸性橙Ⅱ与碱性嫩黄O复合染料水样,确定最佳的混凝剂投药量和pH。对比分析单一方法与联用技术的脱色性能,判断联用技术是否优于单一方法;并探究pH、光催化时间、盐含量、浊度等对脱色性能的影响。结果表明：不同的染料水样,所需的最佳脱色条件不同。处理复合染料水样时,混凝剂最佳投加量为920mg/L,最佳pH为6,经过120min的光催化脱色率可达到78.92%。混凝与光催化联用技术的脱色性能明显优于单一混凝法或光催化法,这与所处理的染料分子结构密切相关。较高的离子强度及浊度会降低混凝剂对染料的吸附电中和与吸附桥连能力,并对光催化剂的表面效应产生抑制,从而降低混凝与光催化联用技术的脱色性能。复合染料水样的盐含量为1200mg/L时,脱色率降幅可达36.87%;浊度为412.2NTU时,脱色率降幅为19.85%。     

含沙高浊水最佳絮凝条件的确定

在含沙量为85kg／m^2的悬浊液中投加阳离子高分子聚合物,研究不同絮凝条件下絮体的自由沉速、结构密实程度、浑液面沉速与上清液余浊等的变化规律。利用“分维”作为定量控制参数研究含沙高浊水絮凝效果迭最佳时的絮凝条件（如搅拌速率、搅拌时间、高分子浓度等）,探讨了最佳絮凝条件下不同原始泥沙浓度对絮体分形结构的影响规律。实验得出85kg／m^2泥沙絮体结构密实性达最佳时的水力剪切强度Ct值存在两个临界值：快速絮凝阶段C1t1=2350,慢速絮凝阶段G2t2=12420。     

聚硅酸铁锌-壳聚糖复合絮凝剂对直接大红染料废水的脱色研究

采用自制的聚硅酸铁锌(PFZSS)与壳聚糖(CTS)制备了新型复合絮凝剂PFZSS-CTS,并研究该絮凝剂对模拟直接大红染料废水的脱色效果。结果表明,适宜的絮凝条件为:投药量40 mg/L,pH=7,沉降时间30 min,快速、慢速搅拌转速分别为130、55 r/min,快速、慢速搅拌分别为时间2.5、15 min,此条件下染料的脱色率达到99.52%。结合ζ电位的分析,初步推断其絮凝机制包括电中和、吸附架桥、网捕卷扫。     

微生物絮凝剂用于染料废水脱色及其动力学研究

从活性污泥中筛选出的一株微生物絮凝荆产生菌,在优化培养条件下所产微生物絮凝剂命名为M-127.将M-127用于染料废水脱色,实验结果表明,废水脱色的最佳条件是:100 mL染料废水中加入0.2 mL M-127和2.0mL CaCL2、体系pH值6.0,200 r/min搅拌1 min,60 r/min搅拌3min,静置15 min.M-127对染料废水的脱色率达到93.88%,同时m还研究了M-127在最佳条件下的脱色动力学m并得到了脱色动力学经验方程.     

腈纶废水生化出水的混凝处理

对腈纶废水生化出水进行混凝处理,通过比较确定三氯化铁为絮凝剂,考察了三氯化铁投加量、助凝剂聚丙烯酰胺投加量、pH对絮凝效果的影响及搅拌速度对絮体的影响.结果表明:当三氯化铁投加质量浓度为90 mg/L,PAM投加质量浓度为2.1 mg/L,搅拌速度为80 r/min时形成的絮体最理想,出水COD、浊度等指标均能满足后续...     

聚硅酸铁(PSF)混凝剂搅拌动力学的特性及理论分析

以水玻璃、硫酸亚铁及氯酸钠为原料，制备聚硅酸铁（PSF）混凝剂；用透射电镜观察PSF的微观形态，针对模拟水及松花江水，采用正交实验从GT值来研究搅拌条件对PSF混凝效果的影响。结果表明，PSF是由许多链节样物种连接而成的分维数很大的敞开式枝状结构，并且形态大小不均，覆盖范围很宽。对于不同的水质，PSF的最佳搅拌动力学条件基本一致，快搅200r／min，2min，慢搅梯度为：60r／min，3min，40r／min，5min，20r／min，2min；快搅和慢搅要密切配合，才能达到最佳的混凝效果；快搅GT值是决定混凝平衡、絮体破碎的关键因素，同时要求适度的快搅速度、稍长的快搅时间，并且要求初始速度较快的慢搅时间较长。     

高分子絮凝剂处理高硬度矿物废水研究

以选矿高硬度废水为处理对象,探讨了絮凝过程中絮凝剂及其用量、pH值的影响。结果表明,絮凝条件为300 r/min搅拌30 s,120 r/min搅拌5 min,80 r/min搅拌10 min,静置5 min(浊度)或30 min(COD和硬度),在pH=12、2.7 mg/L PAM-A6300或PAM-A6100絮凝剂的絮凝效果为:浊度去除率99%、COD去除率56.8%、硬度去除率92.9%,絮体为棉絮状,过滤性能良好,满足废水排放要求。     

磁铁砂加载絮凝技术处理低温低浊海水

采用磁铁砂加载絮凝技术处理低温低浊海水。通过混凝杯罐实验,研究探索了絮凝过程的最佳工艺参数,考察对比了磁铁砂加载絮凝与FeCl3混凝的处理效果。结果表明,混凝剂选用FeCl3、投加量为15 mg/L,磁铁砂粒径为75～125μm、投量为40 mg/L,以先投混凝剂、1 min后投加磁铁砂的顺序进行磁铁砂加载絮凝,可有效去除低温低浊海水中的SS、浊度和有机物。在混凝过程中,以磁铁砂为内核形成了紧密的磁性复合絮体,产生了电性中和、静电及磁场吸附作用,发挥了微砂加载絮凝和磁絮凝的双重优势。与FeCl3混凝相比,不仅处理效果提高,而且药耗减少、沉淀时间缩短、沉降絮体体积压缩,极具应用价值。     

电絮凝处理甲基橙废水的实验及动力学模型

采用电絮凝法处理甲基橙模拟染料废水,研究了染料脱色的影响因素及其COD_Cr去除动力学。考察了静置时间、槽电压、极板间距、初始浓度、pH值以及电解质浓度对甲基橙染料脱色效率的影响。结果表明,槽电压为20 V,电流为0.4 A,极板间距为2.5 cm,废水体积为500 ml,甲基橙初始浓度为500 mg·L^-1,溶液pH值为3.0,电解质KCl的浓度为0.5 g·L^-1时,反应10 min后甲基橙脱色率可达97 %。根据电絮凝的絮凝沉淀理论和氧化反应机理,建立COD_Cr去除反应动力学模型,模型与实验数据拟合较好。通过模型参数的预测可以揭示甲基橙降解主要以絮凝沉淀为主,氧化降解为辅,同时溶液中二价铁Fe(II)的增加会影响COD_Cr去除率的下降。     

Evaluation of mixing conditions using an on-line monitoring technique

Effects of mixing conditions on flocculation were investigated by using a photometric dispersion analyzer (PDA) as an on-line monitoring technique in this study. Both river water and synthetic waters of humic acid (HA) and kaolin solutions were used and polyaluminum chloride (PACl) were used as a coagulant in this study. A clear relationship between F-index and residual turbidity was observed. Residual turbidity was low at high F-index. The mixing effects were also found closely related to the floc formation. When the floc formation was governed by a combination of charge neutralization and sweep floc, rapid mixing was important, but it was not important when the floc formation was governed by the sweep floc mechanism. The coagulant dosage governed the floc size and strength in the sweep floc region. The higher the coagulant dosage was, the larger but the weaker the floc was. Rapid mixing effects were different, depending on raw water characteristics. Fast and large floc formation was observed in flocculation of the kaolin solution, compared to that of the HA solution. Small HA would be mostly adsorbed onto the hydroxide precipitate after the precipitate formed. The adsorption could retard further floc growth. The resulting floc was small, and the floc formation was slow. However, kaolin helped flocculation by bridging the hydroxide precipitates, leading to fast and large floc formation. Temperature affected the flocculation kinetics as well as the floc size. A large floc formed at high temperature. The flocculation kinetics became fast with increasing temperature.     

化学氧化强化三元复合驱污水混凝处理实验研究

为进一步提高原油采收率,国内多数油田开展了三次采油技术的研究和应用。三元复合驱采油废水中残留了大量的聚丙烯酰胺、表面活性剂和碱,油田污水处理常采用混凝处理,由于采出水中含有一定浓度的聚合物,导致采出水的粘度增加,油、水、泥的分离难度增大,常规混凝效果不好,为此需要采取措施强化混凝。本实验采用静态烧杯试验得出,在最佳实验条件:聚合硫酸铁投量为2 500 mg/L、温度为45℃、pH值为6、快速搅拌(200 r/min)2 min后慢速搅拌(80 r/min)5 min、沉淀时间30 min后,水样含油量去除率达64%左右。通过混凝前投加氧化剂强化混凝实验得出:高锰酸钾投量在0.5 mg/L时,除油率提高8%。双氧水投量在5 mmol/L时,除油率提高17%。芬顿试剂中双氧水投量为5 mmol/L,二价铁离子投量在1.5 mmol/L时,除油率提高25%,效果最好。     

聚合氯化铝铁的制备、使用及混凝机制研究

以氯化铝和氯化铁为原料制备出一系列不同铝铁物质的量比及碱化度的无机高分子混凝剂——聚合氯化铝铁（PAFC）,并应用于地表水的混凝处理过程。考察PAFC的混凝效能及产生的絮体特性,进而对其使用条件进行优化并分析混凝机制。结果表明,PAFC为多羟基桥连的铝铁聚合物,水解后发生电中和作用使胶粒脱稳,而后通过羟桥和氧桥联接产生架桥和卷扫沉淀作用,混凝效果优异。PAFC的pH适用范围较宽,但铝铁物质的量比对其水解过程影响较大,在铝铁物质的量比为7:1、碱化度为0.5、投加量为10 mg/L时,絮体的粒度及生长速度最大,此时浊度和UV₂₅₄的去除率分别达84.93%和78.52%。此外,正交实验的结果表明水力条件对PAFC的混凝效能影响显著,其最佳使用条件为：快搅时间为20 s、快搅速度为200 r/min、慢搅时间为15 min、慢搅速度为40 r/min。     

醋酸镁合成工艺的研究

研究了采用镁、醋酸直接反应合成醋酸镁工艺的可行性和反应条件.实验得出,用镁与醋酸反应可以制得无水醋酸镁.在实验条件下,镁与醋酸反应合成醋酸镁的适宜操作条件为:镁与醋酸的质量比为1:8、反应温度为50～120℃、醋酸滴加速率为1.25 mL/min左右、反应时间为2 h,不需要加入催化剂,需要进行快速搅拌.此时,醋酸镁的收率达82%以上.     

利用电石渣和氯化镁制氢氧化镁工艺研究

采用电石渣和盐湖氯化镁为原料制取氢氧化镁。电石渣（氢氧化钙）与氯化铵反应生成氨气,将氨气通入氯化镁溶液中制备氢氧化镁。通过单因素实验和正交实验得出最佳工艺条件：氯化铵与氯化镁物质的量比为5.0,氯化镁浓度为2.0 mol/L,反应时间为60 min,反应温度为25 ℃,陈化时间为2 h。在该条件下氢氧化镁的生成率可达到89%,纯度也可达到98%以上。通过X射线衍射（XRD）及扫描电镜（SEM）表征表明,氢氧化镁产品为片状,粒径在800 nm左右。采用该方法制备氢氧化镁,不仅可以解决电石渣和盐湖氯化镁的大量堆放问题,而且可以制备出高品质的氢氧化镁产品。     

Comparative study of the effects of experimental variables on growth rates of aluminum and iron hydroxide flocs during coagulation and their structural characteristics

In this study, the dimensions of over six thousand flocs were analyzed to quantitatively and comparatively investigate the effects of several experimental variables on the growth rate of aluminum (Al) and ferric (Fe) hydroxide flocs. Results show that Fe hydroxide flocs have faster growth rate than Al hydroxide flocs; and the average size of the former is larger than that of the latter. Increasing the concentration of the bivalent sulfate ion (SO₄²⁻), initial turbidity, or slow mixing rate, was able to increase the growth rate of both kinds of flocs. On the other hand, steady floc sizes were found to decrease with the increase in SO₄²⁻ concentration, initial turbidity, or shear rate. Fe hydroxide flocs are more prone to be influenced by the changes in the variables than Al hydroxide flocs. While the steady floc sizes became smaller when initial turbidity or slow mixing speed increased, the roundness and smoothness of flocs were found to increase, indicating that higher initial turbidity or larger slow mixing rate produces flocs with more regular and round shape. Furthermore, at a fixed shear rate, Fe hydroxide flocs are stronger than Al hydroxide flocs. However, Fe hydroxide floc sizes are much easier to decrease with the increase in slow mixing intensity.     

聚硅酸氯化铁的混凝实验研究及在海水预处理中的应用

用自制聚铁和硅酸钠制备的聚硅酸氯化铁处理模拟水样。考察了絮凝剂的加入量、处理水样的pH值、搅拌速度和搅拌时间等对絮凝效果的影响,同时对自制絮凝剂与市售聚铁铝絮凝剂对海水的絮凝效果做了比较。结果表明:该絮凝剂在加入量为42mg/L、快搅速度为240r/min、慢搅时间为16min、静置30min、酸碱度为中性或略碱性时絮凝效果较好。对海水的探索性实验中,自制絮凝剂优于其它几种。     

Application of combined coagulation-ultrafiltration membrane process for water treatment

The objectives of this research are to identify the membrane fouling potential due to different fractions of NOM and correlate the physicochemical properties of NOM and membranes with the adsorption of humic substances on membrane and investigate the mechanism of coagulation affecting UF, and find the optimum conditions of the combined of coagulation with UF membrane filtration for NOM removal. For Nakdong river water, the humic acid fraction was the most reactive precursor fraction for the formation of the ratio of THMFP/DOC (STHMFP) and TOXFP/DOC (STOXFP). The result of adsorption kinetics tests showed that hydrophobic organics adsorbed much more quickly than hydrophilic organics on both membranes. Thus, hydrophobic compounds exhibited a preferential adsorption onto membrane. In case of the effect of membrane properties on the adsorption of organic fractions, the adsorption ratio (C₁/C_e) was greater for the hydrophobic membrane than for the hydrophilic membrane regardless of the kind of organic fractions. For combined coagulation with membrane process, flux reduction rate showed lower than the UF process alone. Also, the rate of flux decline for the hydrophobic membrane was considerably greater than for the hydrophilic membrane. Applying the coagulation process before membrane filtration showed not only reduced membrane fouling, but also improved removal of dissolved organic materials that might otherwise not be removed by the membrane. That is, during the mixing period, substantial changes in particle size distribution occurred under rapid and slow mixing conditions due to the simultaneous formation of microflocs and NOM precipitates. Therefore, combined pretreatment using coagulation (both rapid mixing and slow mixing) improved not only dissolved organic removal efficiency but also DBP (Disinfection By-Product) precursor's removal efficiency.     

盐湖卤水镁锂沉淀分离工艺研究

采用氨水和氢氧化钠作为沉淀剂,对高镁锂比卤水进行镁的二次沉淀分离以及母液蒸发浓缩提锂工艺进行研究。实验结果表明：常温下,采用质量分数为10%的氨水作为沉淀剂,可使卤水除镁率达到88.6%,实现卤水中镁锂的初步分离;在此基础上,采用氢氧化钠溶液作为沉淀剂,控制浓度为8 mol/L的氢氧化钠溶液的滴加速度为3 mL/min、反应时间为20 min、溶液终点pH=12.5、搅拌转速为120 r/min,采用漏斗过滤氢氧化镁沉淀,卤水的除镁率可达到99.8%。母液经蒸发浓缩析出氯化铵和氯化钠晶体,使锂得到富集。