Control strategies for disinfection byproducts by ion exchange resin,nanofiltration and their sequential combination

● Effects of AER adsorption and NF on DBP precursors, DBPs, and TOX were examined. ● A treatment approach of resin adsorption followed by nanofiltration was developed. ● Both DOC and Br⁻ could be effectively removed by the sequential approach. ● DBPs, TOX, and cytotoxicity were significantly reduced by the sequential approach. Disinfection byproducts (DBPs) are emerging pollutants in drinking water with high health risks. Precursor reduction before disinfection is an effective strategy to control the formation of DBPs. In this study, three types of anion exchange resins (AERs) and two types of nanofiltration (NF) membranes were tested for their control effects on DBP precursors, DBPs, and total organic halogen (TOX). The results showed that, for AER adsorption, the removal efficiencies of DBP precursors, DBPs, and TOX increased with the increase of resin dose, and the strong basic macroporous anion exchange resin (M500MB) had the highest removal efficiencies. For NF, the highest removal efficiencies were achieved at an operating pressure of 4 bar, and the membrane (NF90) with a smaller molecular weight cut-off, had a better control efficiency. However, AER adsorption was inefficient in removing dissolved organic carbon (DOC); NF was inefficient in removing Br⁻ resulting in insufficient control of Br-DBPs. Accordingly, a sequential approach of AER (M500MB) adsorption followed by NF (NF90) was developed to enhance the control efficiency of DBPs. Compared with single AER adsorption and single NF, the sequential approach further increased the removal efficiencies of DOC by 19.4%–101.9%, coupled with the high Br⁻ removal efficiency of 92%, and thus improved the reduction of cyclic DBPs and TOX by 3.5%–4.9%, and 2.4%–8.4%, respectively; the sequential approach also reduced the cytotoxicity of the water sample by 66.4%.     

铜在鲤鱼(Cyprinus carpio)鱼鳃微环境中的形态分布

利用 Playle设计的装置测定了不同铜暴露水平下鲤鱼鳃部进出水中的游离铜离子浓度、粘液含量及有关参数 .用MINTEQA2和单配位体模型联合的试算方法计算了不同形态铜含量以及鳃部粘液对铜的络合能力 .结果表明 ,利用该算法可以获得鱼鳃微环境金属形态分布的准确结果 ,同时可以得到与鱼鳃粘液络合能力有关的参数 .随着暴露铜含量增加 ,粘液分泌量随之增加 ,鱼鳃微环境 p H和碱度也有所上升 .鱼鳃粘液的络合当量浓度 ( Cu/ C)和稳定常数 (对数 )分别为 0 .95mmol/ mg和5.32 .就铜形态分布而言 ,鱼鳃微环境与外部水相的主要差别表现在相对较高的羟基络合态铜含量以及占总量 3%～ 2 0 %的鱼鳃粘液络合态铜 .     

Multifractal characteristics of cylindrical sludge drying

This paper analyzes dewatered sludge drying using the multifractal theory. The drying rates of cylindrical sludge with equal masses but different cross-sectional diameters was studied, from which multifractal parameters such as partition function and quality exponent were obtained. The parameters acquired were used to calculate the multifractal singularity spectrum and indicate the presence of multifractal characteristics. The smaller cross-sectional diameters of the sludge were found to be non-homogeneous, and required quantitative methods to analyze.     

Synergistic effect and degradation mechanism on Fe-Ni/CNTs for removal of 2,4-dichlorophenol in aqueous solution

Environmental Science and Pollution Research - Fe-Ni bimetallic nanoparticles supported on CNTs (Fe-Ni/CNTs) were synthesized, characterized, and applied for removal of 2,4-dichlorophenol (2,4-DCP)...     

An efficient resin for solid-phase extraction and determination by UPLCMS/MS of 44 pharmaceutical personal care products in environmental waters

• A hydrophilic resin (GCHM) was facile synthesis and characterized. • Average absolute recovery of GCHM (75.6%) performs better than Oasis^® HLB. • Detection limits of method (SPE-UPLC-MS/MS) ranged between 0.03 and 0.6 ng/L. • 22 PPCPs were determined in environmental waters ranging from 0.5 to 1590 ng/L. In this study, a hydrophilic resin named GCHM was fabricated based on poly(N-vinyl pyrrolidone-co-divinylbenzene), characterized, and applied as a solid-phase extraction (SPE) material. Up to 44 pharmaceuticals and personal care products (PPCPs) belonging to 10 classes were recovered in environmental water samples. Different variables affecting extraction, such as adsorbent amount, sample pH, and loading speed, were optimized. Under optimal conditions, the average absolute recovery of 44 PPCPs was 75.6% using GCHM, indicating a better performance than the commercial Oasis^® HLB. SPE with home-made hydrophilic polymeric sorbent followed by ultra-performance liquid chromatography and tandem mass spectrometry was validated, and the method achieved good linearity (r²>0.991, for all analytes). In addition, the method detection limits of target compounds ranged from 0.03 to 0.6 ng/L. The developed method was applied to determine PPCPs in 10 environmental water samples taken from the Yangtze River, Huaihe River, and Taihu Lake, 1 groundwater sample from Changzhou in Jiangsu Province, 1 wastewater sample from Xiamen and 2 seawater samples from the Jiulong River in Fujian Province, China. In these samples, 22 compounds were determined at levels ranging from 0.5 to 1590 ng/L.     

Water-Blown Castor Oil-Based Polyurethane Foams with Soy Protein as a Reactive Reinforcing Filler

To decrease the usage of petroleum based materials, a kind of bio-resource based composite foams were developed with soy protein isolate (SPI) as reactive reinforcing filler in castor oil based polyurethane foams (PUF) prepared by self-rising method using water as a blowing agent. The resulting composite foams were evaluated for their morphology, density, mechanical and biodegradation properties, etc. Fourier transform infrared spectroscopy study exhibited characteristic peaks for SPI and PUF and indicated that the amino groups and hydroxyl groups on SPI reacted with polyphenyl polymethylene polyisocyanates (PAPI) to increase the crosslinking degrees of the composite foams. Densities of the resultant composites were found to increase with increasing SPI content. Mechanical properties of the samples were improved with the increase of SPI content. The compost tests further proved that the composite PUF had better biodegradability than neat PUF. Therefore, this research has provided a simple method of preparing the bio-resource based polyurethane foams, while exploring the potential of using SPI in polyurethane foam applications.     

Occurrence and transformations of carbon,nitrogen, and phosphorus related to particle size fraction of sweet potato starch wastewater during hydrolytic acidification processes

Sweet potato starch wastewater (SPSW) is an industrial food-processing waste product, which is a significant pollution source due to its high chemical oxygen demand (COD), nitrogen, and phosphorus loads. The influence of hydrolytic acidification (HA) process on C, N, and P as well as other main parameters were evaluated. It is essential to treat these wastewaters with effective methods such as HA, a general pretreatment application. In this study, we investigate the scientific link between the changes of different fractions of C, N, and P with particle size distribution in response to the newly introduced HA process. Results showed that the levels of COD, TN, and TP remained ultimately stable; pH and suspended solids (SSs) decreased obviously. HA process exhibits excellent capability of reducing the larger particulars (with diameter of >5 μm) into smaller ones (with diameter of <0.1 μm). The most significant initial concentration contribution to COD, TN, and TP pollution came from particles and matter with a diameter of >5 μm, at 41.8, 57.3, and 43.5%, respectively. While the most significant contribution to COD, TN, and TP was resulting from micro-molecular size particles (<0.1 μm) after 48 h. The smallest particles (<0.1 μm) were the most dominant contribution to all pollutants measured, with COD, TN, and TP contributions of 63.2, 50.4, and 59.3%, respectively. While the contribution of larger particles (particle size >5 μm) reduced to 10.2, 15.3, and 7.1%, respectively.

     

Fabrication and Properties of Acid Treated Carbon Nanotubes Reinforced Soy Protein Nanocomposites

Acid treated multiwalled carbon nanotubes (MWNTs) were incorporated into glycerol plasticized soy protein to form MWNTs/soy protein nanocomposite plastics. The influence of the polar groups grafted on carbon nanotubes by acid treatment on the compatibility would be studied. The results showed that aggregation of carbon nanotubes was reduced by acid treatment and some polar groups were grafted on the nanotubes. The modified MWNTs were dispersed in soy protein matrix homogeneously and exhibited good compatibility with soy protein matrix. The crystalline structure of soy protein was not changed by MWNTs. The mechanical properties were dramatically enhanced through MWNTs incorporation due to the strong hydrogen bonding between them and the homogeneously dispersion of MWNTs in protein matrix, indicating the reinforcing effect of MWNTs in soy protein matrix. The water uptake was reduced and the thermal stability was enhanced by MWNTs incorporation.     

小型焚烧设施烟气中二噁英类的排放和控制

对中国典型的小型焚烧设施现状和二噁英类排放进行了初步调查研究,未经处理的小型垃圾焚烧设施烟气中二噁英类毒性当量(TEQ)大于6 ng/m3,小型火化机烟气中二噁英类TEQ大于5 ng/m3.设计并检验了布袋除尘器和活性炭滤布的二噁英类去除效果.仅使用布袋除尘器二噁英类去除率不高,布袋除尘器和活性炭滤布联用可以有效去除飞灰和气相中的二噁英类,去除率达到90%左右,可达到《生活垃圾焚烧污染控制标准》(GB 18485-2001)二噁英类排放标准.     

灰色预测模型及分布活化能模型在废电路板热解中的应用

分别在管式炉反应器和热天平上对废电路板的热解行为进行实验研究。在管式炉反应器上考察了在同一升温速率（20 K/min）下不同热解终温 (400、500、600、700和800℃) 对废电路板热解产物产率的影响。在相关实验数据的基础上尝试用灰色理论及方法建立基于热解终温的废电路板热解灰色产率预测模型GM(1,1),预测结果与实验数据对比表明,该预测模型精度较高,能够较好地对不同热解终温下废电路板热解产物产率进行预测。此外,在热天平上获得的不同升温速率（10、15和20 K/min）下的热失重曲线表明,废电路板的失重速率峰随升温速率的提高逐渐向高温侧移动。采用分布活化能模型对废电路板热失重曲线进行动力学分析,获得废电路板热解活化能的变化曲线。计算结果表明,废电路板热解过程中活化能并不是单一数值,而是随失重率变化的一个函数。所得废电路板热解活化能值在140～250 kJ/mol范围内变化,当失重率在10%～60%之间,活化能值总体呈缓慢上升的趋势,但当失重率＞60%时,活化能值由155.4 kJ/mol迅速增加到244.4 kJ/mol。