Polyacrylamide-grafted legume starch for wastewater treatment: synthesis and performance comparison

Polyacrylamide as traditional flocculant begins to draw the public awareness because of its non-biodegradable nature which may cause the long-term environmental degradation problems. A new high-efficient flocculant was synthesized by legume starch and acrylamide to satisfy the demand of coalmine wastewater treatment. Grafting acrylamide onto mung bean starch was investigated and the characterizations of elemental analysis, scanning electron microscopy, gel permeation chromatography, Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry and nuclear magnetic resonance spectrometer were conducted. The characterization results of the new flocculant prove that acrylamide has grafted onto the mung bean starch molecule chains successfully. Experimental results indicate the optimal synthesis parameters of the new flocculant are: mung bean starch 50 g/L (ethanol solvent), acrylamide 100 g/L, ceric ammonium nitrate 12 g/L, gelatinization temperature 70 °C and copolymerization temperature 70 °C. We also measured and evaluated the performance of the new flocculant on wastewater treatment, and the optimal dosage of the new flocculant is 20 mg/L, with a prominent transmittance of 98.1% and turbidity of 7.82. Experimental results have demonstrated the graft copolymer of acrylamide and mung bean starch owns an outstanding flocculation effect than the traditional polyacrylamide and polyaluminum chloride. The new flocculant has a few features such as environmentally friendly, easy to degrade, fasting sedimentation and low cost, which is especially suitable for the occasions of rigorous environmental requirements and is bound to have broad application prospect for coalmine wastewater treatment.     

Characterization of cationic polyacrylamide‐grafted starch flocculant synthesized by one‐step reaction

Cationic polyacrylamide‐grafted starch (St‐g‐CPAM) flocculant was prepared by using corn starch and acrylamide (AM) as monomers, dimethyl diallyl ammonium chloride (DMDAAC) as cationic monomer through solution polymerization. The effects of initiator, reaction temperature, and monomer concentration on flocculation, the efficiency of grafting, and the yield of grafting were investigated. The results show that the optimal conditions of the polymerization are as follows: the concentration of ceric ammonium nitrate is 0.5%, the reaction temperature is 60°C, the concentration of total monomer is 20%, and the monomer ratio between AM and DMDAAC is 7 : 3. The flocculation capability was characterized by turbidity reduction. The thermal behavior, chemical structure, and microstructure of St‐g‐CPAM were also investigated by thermal gravimetric, IR, and SEM analyses. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of a starch–acrylic acid–chitosan copolymer as flocculant for dye removal

Flocculants prepared with modified natural polymers have recently attracted extensive attention in the field of water treatment. In this work, acrylic acid was successfully grafted onto the backbones of starch and chitosan by free radical polymerization. The synthesis parameters of initiator concentration, reaction temperature, and neutralization degree of acrylic acid were optimized as 0.4 wt %, 50 °C, and 70%, respectively, according to the flocculation performance. The ternary copolymer starch–acrylic acid–chitosan (SAAC) could completely remove Acid Blue 113 from 100 mg/L of simulated wastewater (color removal efficiency 99.7%) at the flocculant dosage of 100 mg/L. The SAAC also had effective flocculation capability in a wide range of flocculant dosages and pH values of wastewater. The ternary copolymer based on two natural polymers has enormous potential as flocculant with its advantages of low price, ecofriendliness, and high performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47437.     

Study of microwave-template initiated copolymerization peculiarity and evaluation on the coal floc distinctive behavior and flocculation performance

Cationic polyacrylamide (CPAM) contains a large number of acylamino and positively charged methyl ammonium chloride groups. It has the advantages of good water solubility, strong adsorption bridging ability, enhanced charge neutralization and destabilization performance, excellent flocculation effect, and wide application. Therefore, CPAM can be used in the treatment of coal washing wastewater, and the research and development of a new flocculant with high efficiency is a hot topic in this field. Template copolymer (TPADM) of methacryloyloxyethyl trimethyl ammonium chloride (DMC) and acrylamide (AM) was synthesized by microwave-template initiated polymerization with sodium polyacrylate (PAAS) as template. The microwave-template initiated polymerization is abbreviated as MW-TP. By analyzing FTIR, ¹H (¹³C) NMR and TG/DSC of TPADM, it was found that TPADM had obvious cationic fragment structure. In addition, the association constant (K_M) and the kinetics of the template reaction showed that the MW-TP was confirmed to be free radical initiated polymerization and I Zip-up (ZIP) polymerization mechanism, which demonstrated the formation of the cationic fragment structure again. This new cationic fragment structure greatly enhanced the ability of charge neutralization, electrical patching and adsorption bridging, thus improving the flocculation performance. Compared with cationic P(AM-DMC) (CPADM), Commercial cationic polypropanamide (CCPAM-1 and CCPAM-2), TPADM had better flocculation effect on coal washing wastewater. Under the optimum flocculation conditions (dosage = 16 mg/L, pH = 7.5), suspended solid (SS) concentration and turbidity of coal washing wastewater treated by TPADM reached 14.3 mg/L and 8.7 NTU, respectively. The floc formation, breakage, and regeneration analyses showed that the cationic fragment structure in TPADM could contribute to the formation of large and high density flocculation structure (d₅₀ ≥ 245 μm, D_f ≥ 2.05), and these coal flocs can regenerate rapidly after being broken. Finally, these large and compact flocs help to accelerate the flocs sedimentation and reduce the SS concentration and turbidity of coal washing wastewater, and enhance the effect of solid–liquid separation.     

自制交联阳离子淀粉絮凝剂处理含油废水

以自制的马铃薯交联阳离子淀粉为絮凝剂,对某炼油厂的含油废水进行絮凝实验,以COD去除率和油去除率为指标,得到絮凝剂最佳投加量,在此基础上考察了pH和水温的影响.实验结果表明:絮凝剂的最佳投加量为4 650 mg/L、pH为1.5～4、温度为50℃时,该絮凝剂对含油量和COD的去除效果较好.     

氧化-聚硅酸锌混凝法处理厌氧生化淀粉废水的研究

采用聚硅酸锌絮凝剂处理淀粉生产废水的厌氧生化出水,试验考察了废水pH值、絮凝剂投加量、搅拌速率等因素对絮凝效果的影响,以及高锰酸钾预氧化后再絮凝处理的效果.试验结果表明,在PSAZ投加量为0.5 mL/L、pH值为8.75、快速搅拌速率为285r/min、慢速搅拌速率为60r/min的最佳条件下,废水中CODCr的去除...     

玉米淀粉改性阳离子絮凝剂的制备

以玉米淀粉为原料,经糊化后,加入阳离子化试剂,合成了阳离子性改性淀粉絮凝剂SF.以生活污水为处理体系,探讨了SF的絮凝性能.在30 mg/L时,SF对高浊度207 NTU高岭土悬浮液达到最好的处理效果,出水浊度在10 NTU以下.对生活污水中COD有一定的去除效果.SF作PAC的助凝剂处理湖水,比单独投加PAC絮凝剂有更好的处理效果,浊度去除率都在90%以上     

阳离子型改性淀粉对稠油废水絮凝性能考察

合成了三种具有不同阳离子度的阳离子型改性淀粉接枝共聚物絮凝剂ZHYC-n,考察了这三种絮凝剂与PAC复配对稠油废水的絮凝性能,并与市售阳离子型聚丙烯酰胺絮凝剂CPAM进行了对比.絮凝实验结果表明,ZHYC-n与PAC复配具有优良的絮凝脱油脱硫效果,随阳离子度增加絮凝效果显著增加.阳离子型絮凝剂分子链上的阳离子电荷密度不是影响絮凝效果的惟一主要因素,阳离子型改性淀粉接枝共聚物具有的多支链型结构可以明显的提高絮凝剂的絮凝效果.     

Cationic starch for microalgae and total phosphorus removal from wastewater

The city of Logan, Utah treats wastewater in 460 acres of facultative lagoons. Naturally growing algae in these lagoons uptake nutrients and remediate the wastewater, but require coagulation and flocculation for separation from wastewater. Cationic corn starch and cationic potato starch with a degree of substitution 1.34 and 0.82, respectively, were synthesized using 3‐methacryloyl amino propyl trimethyl ammonium chloride and tested on Scenedesmus obliquus and lagoon wastewater. The zeta potential of the cationic starches tested over a pH range 5.0–10.0 showed an average of +16.0 and +15.1 mV for cationic corn starch and cationic potato starch, respectively. Total suspended solids removals of 90 and 85% were achieved with cationic corn starch and cationic potato starch, respectively, when tested with S. obliquus. Tests with wastewater showed total suspended solids removals of 80 and 60% for cationic corn starch and cationic potato starch, respectively. Total phosphorus removal values from wastewater were approximately 33, 29, and 42% for cationic corn starch, cationic potato starch, and alum, respectively, for a coagulant/algae ratio of 1.4 (wt/wt). These results indicate that cationic starch has the potential to replace alum for algae harvesting and wastewater treatment making it a suitable alternative to inorganic coagulants and flocculants. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2572–2578, 2013     

高取代度阳离子淀粉处理造纸白水的研究

采用实验室研制的高取代度阳离子淀粉作为絮凝剂对造纸白水进行处理,通过实验探讨了高取代度阳离子淀粉的加入量、废水的pH值及絮凝时间对絮凝效果的影响,确定了高取代度阳离子淀粉处理造纸白水的最佳条件为:阳离子淀粉的投加量为200mg/L,不调pH值,絮凝时间为24h。     

β‐Cyclodextrin modified cationic acrylamide polymers for flocculating waste drilling fluids

In this article, the P(AM/A‐β‐CD/DMDAAC) is used as flocculant. The synthesis and characterization of the cationic polyacrylamide flocculant modified by β‐cyclodextrin have been studied in the early article. This article stresses its excellent flocculated performance and mechanism. In the flocculated process, the bridging flocculation played a dominant role. Through the flocculation experiments, it can be seen that the flocculating rate of the P(AM/A‐β‐CD/DMDAAC) on four solutions can go up to 93.4%, 89.7%, 85.1%, and 96.7%, respectively. As can be seen from experiment data, the flocculated property of P(AM/A‐β‐CD/DMDAAC) is superior to polyacrylamide and poly (dimethyl diallyl ammonium chloride). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40197.     

Flocculation properties and adsorption kinetics of cationic starches in kaolin suspensions

The flocculation characteristics of cationic starches with degree of substitution (DS 0.32–0.63) have been evaluated in 1.0 wt % kaolin suspension by spectrophotometry and colloid titration. Cationic starch is found to be an effective flocculant for removal of anionic suspension particles. Changes in the electrokinetics of kaolin as a function of pH were investigated in the absence of flocculant. The results show that kaolin in water exhibits a negative surface charge at pH > 2.5. The negative hydrophilic surface sites of kaolin are responsible for the adsorption of cationic starch molecules. The experimental data of the adsorption of cationic starch (DS 0.51) follow a Langmuir isotherm with maximum adsorption capacities of 16.89 mg/g. For the adsorption of cationic starch, chemical reaction seems significant in the rate‐controlling step and the pseudosecond‐order chemical reaction kinetics provides the best correlation for the experimental data. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

辽河油田稀油二元复合驱采出污水絮凝处理研究

对辽河油田稀油二元复合驱采出污水进行絮凝处理。优选了无机、有机絮凝剂,考察了复配絮凝剂效果及其加药方式对絮凝效果的影响,研究了不同絮凝剂产生的絮体形态。结果表明,优选的无机絮凝剂为聚合氯化铝(PAC),有机絮凝剂为阳离子聚丙烯酰胺(CPAM),其絮凝效果随阳离子度的提高而提高。有机絮凝剂投加量对复配絮凝剂的处理效果影响较大。适宜的复配药剂投加量为PAC 300 mg/L、CPAM-1 4 mg/L,处理后污水SS的质量浓度为10.65 mg/L、油的质量浓度为2.43 mg/L、透光率为84.0%,絮体较致密。最好的加药方式为投加完无机絮凝剂后,立即加入有机絮凝剂。不同的絮凝剂形成的絮体形态不同,复配时CPAM-1的投加量越大,絮体越致密。     

淀粉接枝丙烯酸聚合型絮凝剂的合成及絮凝性能研究

以可溶性淀粉为主要原料,以丙烯酸为接枝单体,硝酸铈铵和过硫酸钾为复合引发剂,采用溶液聚合的方法对糊化处理后的淀粉进行接枝聚合,合成出环保型淀粉衍生物水处理絮凝剂。通过对接枝聚合反应温度、反应时间、引发剂用量以及丙烯酸单体用量等因素对接枝率影响的研究,确定较佳的接枝产物合成条件：淀粉10g,单体丙烯酸用量10mL,硝酸铈铵和过硫酸钾（摩尔比1：1）复合引发体系用量2mmol,接枝反应温度50℃,接枝反应时间3h,接枝率达到43．2％。利用选煤后的废水对其产品絮凝性能进行实验研究,确定较佳的废水絮凝处理条件。     

微生物絮凝剂生产条件的优化

以淀粉废水为碳源培养高产絮凝剂的菌株NII4,研究培养菌投加量、温度、通气量、氮源和氮投加量对微生物絮凝剂絮凝效果的影响。结果表明,微生物絮凝剂的最佳培养条件是:菌悬液投加量为3 mL、温度为30℃、摇床转速为160 r/min,淀粉发酵培养基中有机氮源脲与无机氮源硫酸铵复合使用最佳比的情况是:当总氮的质量浓度为500 mg/L时,脲与硫酸铵的质量比为3∶2,此时絮凝率最高达91.58%;当总氮的质量浓度为200mg/L时,脲与硫酸铵的质量比为3∶1,此时絮凝率最高达90.88%。     

Synthesis,characterization, and flocculation properties of poly(acrylamide‐methacryloxyethyltrimethyl ammonium chloride‐methacryloxypropyltrimethoxy silane)

A novel hydrophobically modified and cationic flocculant poly(acrylamide‐methacryloxyethyltrimethyl ammonium chloride‐methacryloxypropyltrimethoxy silane) (P(AM‐DMC‐MAPMS)) was synthesized by inverse emulsion polymerization. The molecular structure of hydrophobically cationic polyacrylamide (HCPAM) was characterized by FTIR and ¹H‐NMR. The effects of DMC and MAPMS feed ratio on intrinsic viscosity and solubility were measured. The effects of hydrophobically cationic flocculants on reactive brilliant red X‐3B solution and kaolin suspension were studied. It was found that the introduction of MAPMS could increase the intrinsic viscosities of P(AM‐DMC‐MAPMS) and enhance the flocculation properties to anionic dye solution and kaolin suspension, but reduced their water‐solubility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

季铵型阳离子淀粉絮凝剂的微波干法合成、结构表征及应用研究

以3-氯-2-羟丙基三甲基氯化铵为阳离子醚化剂,天然淀粉为原料,微波干法合成具有絮凝、杀菌等功能季铵型阳离子淀粉絮凝剂。研究了各种因素对合成的影响,确定了最佳反应条件。结果表明：在阳离子醚化剂与淀粉摩尔比0．35,NaOn与阳离子醚化剂摩尔比1．2,微波功率184W,辐射时间5min时,产物相对粘度为3．18（0．5％）左右,阳离子取代度为0．31。所得产品与无机絮凝剂PAC复配后具有较好的絮凝及杀菌效果。     

微波干法制备阳离子淀粉絮凝剂及其应用

以3—氯—2—羟丙基三甲基氯化铵为阳离子醚化剂，天然物质淀粉为原料，微波干法制得季铵型阳离子淀粉絮凝剂。通过正交试验，研究了各种因素对合成的影响，确定了最佳反应条件。结果表明：阳离子醚化剂与淀粉摩尔比0．35、NaOH与阳离子醚化剂摩尔比1．2、微波功率184W、辐射时间5min时，产物相对黏度为3．18，阳离子取代度为0．31。     

Characterization of cationic starch: An efficient flocculating agent

Starch is a known carbohydrate in which, regardless of its origin, two polysaccharides are found namely amylose and amylopectin. By insertion of a cationic moiety to the backbone of starch, a modified cationic starch can be developed which can be used as flocculant. Various grades of cationic starches were developed to optimize the best performing flocculant. The base polysaccharide, starch and the best performing cationic starch i.e., Cat St3 (which have been confirmed from flocculation characteristics and intrinsic viscosity measurement) have been characterized by various characterization techniques such as determination of molecular weight, elemental analysis, FTIR spectroscopy, intrinsic viscosity measurement, thermal analysis, etc. From the characterization, it could be concluded that there was a substantial incorporation of cationic moiety onto the backbone of starch. The flocculation efficacy of these cationized starches was compared with each other and with some of the commercial flocculants available in national and international market in manganese ore suspensions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

元宝枫水提取液的絮凝研究

研究了阳离子淀粉絮凝剂对元宝枫水提取液的絮凝作用;比较了不同工艺对产品的影响。结果表明:采用阳离子淀粉絮凝剂,澄清时间由醇沉法的48 h缩短为6 h;在阳离子淀粉质量浓度为150 mg/L、絮凝温度为60℃、提取液pH为6.0时,澄清液透光率、总黄酮质量分数分别达90.6%、23.2%。