Removal of organic matter by coagulation enhanced with adsorption on PAC

The removal of humic acids and phenol from model solution by coagulation and adsorption on powdered activated carbon (PAC) was investigated. A PAX XL-69 polyaluminum chloride was applied as a coagulant. The adsorption of humic acids and phenol on activated carbon for single- and bi- component solutions was studied. It was found that coagulation without PAC addition was less effective than the adsorption-coagulation integrated system. Coagulation enhanced with adsorption on activated carbon was more effective when coagulation was preceded by adsorption than when the two processes were carried out simultaneously. The best results were obtained at pH 7. Phenol and color were removed pletely, UV₂₅₄ absorbance was reduced by about 99% and COD-Mn was reduced by 81-89%.     

自然有机物对地下水混凝除铁的影响试验研究

通过模拟试验,考察了自然有机物的浓度、分子质量以及溶液的pH、温度对地下水混凝除铁的影响,并研究了预氧化在混凝除铁中的作用.结果表明,有机物的浓度越高、分子质量越大,有机铁的去除率越高.当Fe2 与分子质量＞10 ku的有机物络合时,用混凝除铁能取得良好的效果;当Fe2 与分子质量＜4 ku的有机物络合时,采用预氧化混凝工艺能达到较好的除铁效果.在pH6.0～7.5的范围内,降低pH有利于混凝除铁.温度升高对混凝除铁有利.     

天然有机物对混凝除藻的影响

试验研究了天然有机物(腐植酸、富里酸)对混凝除藻的影响,以及在含有天然有机物水体中混凝除藻的机理.结果表明,天然有机物会与藻细胞争夺絮凝剂,由于天然有机物与PAC亲和力强,PAC优先与天然有机物结合,再与藻细胞结合,当水体中天然有机物含量较多时,混凝除藻效果降低.当腐植酸质量浓度为20.2 mg/L时,藻去除率仅为2....     

DBPs formation and toxicity monitoring in different origin water treated by ozone and alum/PAC coagulation

In this study, aluminium sulphate (alum) and polyaluminum chloride (PAC) coagulation were used for coagulation of different origin water (Buyukcekmece, BC and Omerli, OM in Istanbul, Turkey and Carmine, CR in Salerno, Italy) treatment. The effect of pre-ozonation alone and combined with coagulation on NOM removal which was characterized by TOC, UV254 was investigated. DBPs formation and acute toxicity on Daphnia magna of chlorinated raw and treated samples were defined in parallel. Moreover, bromide spiking was evaluated for DBPs speciation. Optimum alum dose for TOC removal was found to be 40 mg/L for OM while 80 mg/L of alum exhibited the lowest total trihalomethane formation potential (TTHMFP). Pre-ozonation enhanced the removal of TOC and reduction of TTHMFP when it was used in combination with both coagulants. In contrast, total haloacetic acid formation potential (THAAFP) increased after each coagulation, ozonation and their combination. 300 µg/L bromide spiking (around the same level with BC) in raw sample collected from CR increased the formation of brominated disinfection byproducts. Raw and treated samples displayed acute toxicity on Daphnia magna in different pattern and practically “no dose-response behavior” was observed.     

Distribution of inorganic and organic substances in the hydrocyclone separated Slovak sub-bituminous coal

A low-rank Slovak sub-bituminous coal from the Handlová deposit was physically treated by washing in a water-only cyclone with the goal to find the separation effect for inorganic (mainly Fe-bearing minerals) and organic substances (humic acids, diterpanes). A high-quality coal product with the ash content in the dry matter of 9.02% and carbon content of C^d = 68.12% at a mass yield of 29.51% was obtained using the water-only cyclone processing. At first, the physically treated coal samples were detailed characterized by XRD, ⁵⁷Fe Mössbauer spectroscopy, FT-IR and HR-TEM. In addition to non-crystalline organic coal components, inorganic compounds belonging to silicate minerals (kaolinite, muscovite and quartz) as well as to Fe-bearing sulphide minerals (pyrite) were identified in the sub-bituminous coal by XRD. ⁵⁷Fe Mössbauer spectroscopy detected the presence of iron carbonate (siderite), iron-containing clay mineral and two sulphur-containing minerals (pyrite, jarosite) in the untreated coal. On the other hand, only one Fe-bearing mineral, (pyrite) was found in the washed coal. Effect of the physical separation is also demonstrated in FT-IR spectra, where the peak at 1040 cm⁻¹ representing the silicate component in the untreated sample is not detectable in the washed coal sample. Presence of extractive organic substances, i.e. humic acids and tetracyclic diterpane (16α(H)-phyllocladane), in the hydrocyclone products is also evidenced. It was confirmed that the isolated diterpenoic compound is attendant in the washed product with the lowest ash content and it is assimilated with the organic part of coal. Surprisingly, humic acids were found in the highest concentration in the slurry that has the highest content of ash (63.14%).     

Natural organic matter and formation of trihalomethanes in two water treatment processes

The investigation involved the study of performance of two local plants' slightly different treatment processes for the removal of natural organic matter (NOM) which comprises trihalomethane (THM) precursors. Ultrafiltration separated the contained NOM into various apparent molecular weight (AMW) fractions to reveal the two processes NOM removal efficiencies, in terms of dissolved organic carbon (DOC), UV absorbance (UV254) and THM formation potential (THMFP). DOC and UV254 levels of source water at both plants tested low and they concentrated in the portion with AMW less than 3,000 Daltons. The combined expression of UV254 with DOC as specific ultraviolet light absorbance (SUVA) indicated that the source water of Macau had a value less than 3 L/mg-m. Therefore the main DOC content was fulvic in character, which is difficult to remove and favors the formation of brominated THMs. Low DOC removal percentages recorded in both processes confirm this observation. However, both processes showed similar removal efficiency of around 50% on humic substances and THM precursors quantified by measurements of UV254 and THMFP, respectively.     

高锰酸盐复合药剂强化混凝处理高有机物含量的地表水

用高锰酸盐复合药剂强化混凝处理,对受高浓度有机物放心水污染的地表水进行了试验研究,结果表明,仅用硫酸亚铁氯化法混凝处理时,原水CODMn浓度增加使混凝效果变差,混凝曲线的最佳药量范围变窄,处理后水质难以达到要求,高锰酸盐复合药剂有显著强化混凝效能,其强化混凝效果与投加方式有关,高锰酸盐复合药 硫酸亚铁混凝剂之后投加的混凝效果最好,投加主锰酸盐复合经剂强化处理使混凝曲线向下移动且向两极张开,拓宽了最佳混凝剂投量范围,提高了系统了抗干扰或抗冲击性,高锰酸盐复合药剂最佳投量与原水CODMn之间符合双矩形双曲线方程y=4\854x/(25.527 x).     

Thin films of organic polymer composites with inorganic aerogels as dielectric materials: polymer chain orientation and properties

Summary High temperature poly(p-phenylene biphenyltetracarboximide) nanocomposite films with inorganic particulates, which are applicable to the fabrication of microelectronic devices, were prepared from the poly(amic acid) and silica aerogels with a size of ca. 150 nm in diameter by solution blending and subsequent conventional polyimide film formation process. The structure and properties were measured. By the composite formation, the optical and dielectric properties were improved due to the low dielectric constant characteristic of silica aerogels, whereas the interfacial stress and thermal expansion coefficient were significantly degraded by a large disturbance in the polymer chain in-plane orientation caused by silica aerogels despite of their low thermal expansivity. This indicates that in the rigid type of polymer composites with inorganic particulates, the orientation of polymer chains still plays a critical role on the physical properties.     

强化混凝处理碎煤加压气化废水生化水中有机物的实验研究

碎煤加压气化废水生化出水分别用混凝剂PAC和PFC进行强化混凝处理,考察出水有机物（TOC）的去除率.结果表明,采用强化混凝工艺可有效降低水中的有机物,随着混凝剂加药量的增大,有机物的去除率升高,并且使用PFC的效果要优于使用PAC的效果.PAC和PFC分别对应不同的最优混凝水力条件,采用PFC的最优混凝水力条件为混合转速100 r/min,混合时间3 min,反应转速60 r/min,反应时间30 min;采用PAC的最优混凝水力条件为混合转速100 r/min,混合时间0.5 min,反应转速60 r/min,反应时间30 min.     

固废基无机高分子混凝剂研究进展及改进途径

无机高分子复合型混凝剂具有优越的絮凝能力,但目前于基于固废资源化利用制备无机高分子复合混凝剂的相关研究缺乏系统性。本文介绍了三类固废基无机高分子复合混凝剂的制备工艺、性质特点,简述了其在水处理领域的应用、作用机理及存在的问题,并结合新型无机高分子复合混凝剂的研究进展,分析了固废基无机高分子复合混凝剂的发展方向。根据已有结果,文中指出需要从固废原料的化学组成,建立全面的固废资源,优化不同来源固废基无机高分子复合混凝剂的制备工艺;其次指出应进行混凝剂的物耗、能耗等技术经济分析,促进其规模化生产使用;并提出对污泥固废应进行循环资源化利用,关注制备过程中产生的无机盐,避免对水质的不良影响;最后表明,应加强混凝剂功能化研究,开发具有协同效应的固废基无机高分子复合混凝剂。     

焦化废水中有机污染物的混凝去除作用机理探讨

烧杯搅拌实验和混凝前后水样中有机污染物的ＧＣ／ＭＳ分析结果表明,焦化废水中有机污染物的混凝去除机理主要是络合沉降和絮体吸附。各有机污染物的云除率与其分子结构密切相关,易在氢氧化物絮体上吸附或具有络合基团且无空间位阻的有机污染物,易被混凝去除。     

Photoelectrocatalytic humic acid degradation kinetics and effect of pH,applied potential and inorganic ions

This study addresses the removal of humic acid (HA) dissolved in an aqueous medium by a photoelectrocatalytic process. UV₂₅₄ removal and the degradation of color (Vis₄₀₀) followed pseudo‐first order kinetics. Rate constants were 1.1 × 10^?1 min^?1, 8.3 × 10^?2 min^?1 and 2.49 × 10^?2 min^?1 (R² > 0.97) for UV₂₅₄ degradation and 1.7 × 10^?1 min^?1, 6.5 × 10^?2 min^?1 and 2.0 × 10^?2 min^?1 for color removal from 5 mg dm^?3, 10 mg dm^?3 and 25 mg dm^?3 HA respectively. Following a 2 h irradiation time, 96% of the color, 98% of the humic acid and 85% of the total organic carbon (TOC) was removed from an initial 25 mg dm^?3 HA solution in the photoanode cell. Photocatalytic removal on the same photoanode was also studied in order to compare the two methods of degradation. Results showed that the photoelectrocatalytic method was much more effective than the photocatalytic method especially at high pH values and with respect to UV₂₅₄ removal. The effect of other important reaction variables, eg pH, external potential and electrolyte concentration, on the photoelectrocatalytic HA degradation was also studied. Copyright © 2003 Society of Chemical Industry     

Evaluation of adsorption and coagulation characteristics of humic acids preceded by alternative advanced oxidation techniques

Humic substances mainly humic acids constitute the major fraction of natural organic matter in water supplies. Humics express diverse actions primarily related to the formation of potentially harmful disinfection by products (DBPs). Therefore, the removal of DBP precursors through numerous treatment techniques gains high importance. Besides the conventional treatment processes, the applications of advanced oxidation techniques are considered as effective tools for the elimination of humic acids (HAs) from natural waters. In the present study, both the adsorption and coagulation characteristics of humic acid samples are evaluated subsequent to pretreatment by photocatalytic oxidation and ozonation. The changes in preoxidized humic acid solutions are assessed in relation to the alterations induced in the UV-vis and fluorescence spectroscopic properties. The removal efficiency of color in terms of Color₄₃₆ and aromaticity with respect to UV₂₅₄ are presented relevant to each treatment step. Major key parameters such as the selection of coagulant types (alum and ferric chloride), coagulant aids (ionic and non-ionic polyelectrolyte) and optimum coagulant dose were comparatively discussed. The adsorption characteristics of powdered activated carbon (PAC) and granular activated carbon (GAC) were investigated.     

无机高分子絮凝剂混凝吸附性能的比较研究

比较了无机高分子絮凝剂聚合硫酸铁(PFS)、聚合氯化铝(PAC)和聚氯硫酸铁(PFCS)在废水处理中的混凝吸附性能，并对絮凝剂的混凝机理进行了初步探讨。研究结果表明，在使用量相同的情况下，聚铁的絮凝性能明显优于聚铝，经改性后的PFCS使用的pH范围更宽，混凝除浊效果更好。在选定的实验条件下，经砂滤、絮凝、活性炭吸附处理后，水样中CODCr,浊度、色度和SS的去除率均在80％以上，出水可达到国家污水综合排放标准。     

The synthesis of humic acids graft copolymer and its adsorption for organic pesticides

humic acid graft copolymer (PSt-g-HA) was prepared by graft copolymerization of Humic acid (HA) with styrene and the sorption of three selected organic pesticides, parathion-methyl, carbaryl and carbofuran by PSt-g-HA acid and untreated humic were also examined, respectively. The PSt-g-HA had relatively high aromatic carbons content because the grafted copolymerization of polystyrene entered into condensed domains in HA, whereas the removal of the polar function groups, such as carboxyl and phenolic hydroxyl group, was performed. For above reasons, the sorption capacity of three organic pesticides (parathion-methyl, carbaryl and carbofuran) on PSt-g-HA increased by 64.1% to 95.2%.     

铝盐混凝剂处理胜利油田聚合物驱采出水混凝机理研究

研究了铝盐混凝剂处理胜利油田聚合物驱采出水的效果和作用机理.结果发现:原油、部分水解聚丙烯酰胺(HPAM)和盐共存时,三者相互作用结果都导致混凝剂投加量增加,除油、除HPAM效果降低.在处理实际采出水时,混凝效果主要依靠Al~(3+)与水中残余HPAM的交联作用.采出水中油滴和盐都会阻碍铝盐与HPAM的交联反应.与HPAM交联能力较强的硫酸铝的除油效果和去除HPAM效果比聚合氯化铝(PAC)高.     

聚合硫酸铝钛的制备与结构表征

以硫酸铝、硫酸钛为原料制备无机复合高分子混凝剂聚合硫酸铝钛（PATS）。采用Ferron逐时络合比色法、红外光谱、X射线衍射、扫描电镜与能谱对产物中Al的形态、结构形貌、组成进行表征分析。采用单因素实验法获得最佳合成条件：反应温度50℃、n（Ti）/n（Al）为0.3∶1与n（OH）/n（Ti+Al）为0.3∶1。形态分析表明n（OH）/n（Ti+Al）、反应温度与n（Ti）/n（Al）对Al形态分布均存在影响,且n（OH）/n（Ti+Al）与n（Ti）/n（Al）对Al形态影响较大。随着n（OH）/n（Ti+Al）增大,Al_a含量逐渐降低,Al_b与Al_c含量逐渐升高;随着n（Ti）/n（Al）的增大,Al_a含量逐渐升高,Al_b与Al_c含量逐渐降低;随着反应温度升高,Al_a为主要形态,其含量在78.94%～85.49%,且Al_a、Al_b都呈现先减小后增大的趋势,Al_c含量则呈现先增大后减小的趋势。红外光谱与X射线衍射结果表明硫酸铝与硫酸钛发生了聚合反应,生成了高分子聚合物;扫描电镜表明PATS形貌团簇,呈网状结构,有助于吸附架桥和网捕卷扫,增强了PATS的混凝性能。     

赶酸仪外加热测定土壤中有机质含量

以Ag_2SO_4为催化剂,在硫酸、重铬酸钾溶液中,采用赶酸仪外加热消煮促进有机质氧化分解,并计算土壤有机质的含量。方法检出限为0.102g/kg,检出下限为0.410g/kg。对国家标准物质GBWO7459,GBW07460,GBW7461,GBWO7414a分析验证,测定分析结果与标准值吻合。操作简便快捷,准确性高,满足土壤样品中有机质的测定,适用于批量土壤样品测定。     

Plant availability of inorganic and organic selenium fertiliser as influenced by soil organic matter content and pH

The objective of the present study was to investigate the influence of soil organic matter content and pH on plant availability of both inorganic and organic selenium (Se) fertilisers. Further, the risk of Se leaching after application of inorganic Se fertiliser was evaluated. A new interpretation of an older field study at different sites in Southern Norway showed that organic C was correlated with grain Se concentration in wheat, barley and oats, explaining up to 60% of the variation in Se concentration. Pot experiments with a peat soil, a loam soil and a peat/loam soil mixture were conducted for the present study at a range of pH values between pH 5 and 7. Below pH 6, Se uptake from added Se fertiliser was higher in the soil types with high organic matter content than in the loam. The opposite occurred at a soil pH above 6, where Se uptake was higher in the loam than in the peat soil. A simple leaching experiment after one growing season confirmed the findings of the pot experiments that Se availability in the loam soil with a relatively low organic matter content increased with increasing pH, whereas it decreased in the peat soil. Neither Se yeast, nor pure Se methionine, used as organic Se fertiliser, resulted in any significant uptake of Se when added at concentrations similar to the inorganic Se applications.