中水深度处理后续反渗透系统的化学清洗

通过分析反渗透装置运行参数的变化、保安过滤器的污堵情况以及SDI微孔滤膜的截留物分析结果,判断反渗透膜主要受微生物和有机物污染,同时可能有无机盐垢形成复合污染,并据此确定了杀菌+碱洗+酸洗的清洗工艺。反渗透经化学清洗后进水压力大幅降低,系统出力显著提高,取得了令人满意的清洗效果。     

市区交通干道路面沉积物理化特性分析

通过对某市区主要交通干道路面沉积物理化特性的监测分析,得出研究区域路面沉积物的基本物理化学性质,包括街道灰尘的pH、有机质和其粒径分布特征.同时,还分析了不同季节路面沉积物理化特性.     

Exploratory analysis of excitation-emission matrix fluorescence spectra with self-organizing maps—A tutorial

Large datasets are common in chemical and environmental engineering applications and tools for their analysis are in great demand. Here, the outputs of a series of fluorescence spectroscopy analyses are utilised to demonstrate the application of the self-organising map (SOM) technique for data analysis. Fluorescence spectroscopy is a well-established technique of organic matter fingerprinting in water. The technique can provide detailed information on the physico-chemical properties of water. However, analysis of fluorescence spectra requires the application of robust statistical and computational data pre-processing and analysis tools.This paper presents a tutorial for training engineering postgraduate researchers in the use of SOM techniques using MATLAB^®. Via a tutorial, the application of SOM to fluorescence spectra and, in particular, the characterisation of organic matter removal in water treatment, is presented. The tutorial presents a step-by-step example of the application of SOM to fluorescence data analysis and includes the source code for MATLAB^®, together with presentation and discussion of the results. With this tutorial we hope to popularise this robust pattern recognition technique for fluorescence data analysis and large data sets in general, and also to provide educational practitioners with a novel tool with which to train engineering students in SOM.     

钙元素对褐煤热解和气化特性的影响

综述了钙元素对褐煤热解和气化特性的影响,讨论了钙元素对热解产物中挥发分、焦油产率和气体产物分布的影响,以及对褐煤半焦气化的催化作用。结果表明,与酸洗煤相比,热解过程中,钙元素降低焦油产率,提高半焦产率;气化过程中,钙元素的植入提高褐煤半焦的反应活性,缩短了反应时间。高温时钙元素主要以氧化态的形式存在,低温时则不断与半焦基体键合而参与交联反应,少部分挥发。     

稠油石化污水有机污染物分布特征研究

采用Gc-MS分析方法,研究了稠油石化污水中有机物分布特征,分析结果表明,稠油石化污水中有机物以烷烃、酚类和有机酸为主并含有一定量的PAHs,污水中有机物分子量140以下的以酚类为主,分子量在140以上的有机物多为烷烃和PAHs,其中烷烃类主要为分子量在200～350的饱和烷烃为主,PAHs以含不同数量甲基取代基的萘为主.     

压铸用可溶性盐芯的工艺研究

本文对压力铸造中适用的可溶性盐芯的工艺进行了较全面的研究,在实验的基础上,对其最佳配方、形成工艺、烧结工艺、性能检测以及在压铸中的应用和盐芯的溶解等方面,做了大量工作,取得具有实践意义的资料。实验证明:运用可溶性盐芯可以有效地简化模具没计、降低生产成本,有一定的使用价值。     

基于广义隐马尔可夫模型的PM2.5浓度预测

近年来,以PM_2.5为主要污染物的重霾污染事件频频发生,给我国国民经济和居民健康造成了严重损失。在空气质量尚未得到根本性改善的情况下,对重霾污染的准确预警不仅能使公众合理回避污染危害,还能为政府实施应急管理提供时间裕量。针对影响PM_2.5浓度的前体物及气象因素的非高斯分布特点以及传统隐马尔可夫模型（hidden Markov model,HMM）必须已知隐含状态个数的缺点,采用广义隐马尔可夫模型（generalized hidden Markov model,GHMM）对北京市除去定陵外的11个国控站点2013年1月～2017年1月的PM_2.5浓度进行了预测。结果表明：GHMM对严重污染及以上PM_2.5样本浓度预测准确率显著高于传统连续HMM,但针对中度污染及以下PM_2.5样本浓度的预测准确率接近传统HMM。     

Characterization of EfOM Fraction Responsible for Short-Term Fouling in Ultrafiltration

Based on our earlier diagnosis that hydrophobic and hydrophilic (HPO/HPI) acids are the primary cause of short-term fouling in the ultrafiltration of secondary effluent, the HPO/HPI acids were extracted and subsequently characterized in comparison with commercial organic materials. HPO/HPI acids isolated from secondary effluent contained significantly fewer complex mixtures than humic substances that have been implicated as the dominant foulants in the filtration of surface water using porous membranes. The physicochemical and spectroscopic characterization demonstrated that the aromaticity and apparent molecular weight of HPO/HPI acids were lower than that observed for other humic materials, while the oxygenated functional groups were relatively higher.     

Osmotic dehydration of lemon (Citrus limon L.) slices: Modeling mass transfer kinetics correlated with dry matter holding capacity and juice sac losses

Osmotic dehydration of lemon slices was performed using hypertonic NaCl solution. Due to low dry matter holding capacity (DHC) of lemon, the moisture loss, salt gain, and solid loss kinetics during osmotic dehydration were studied by considering the loss of juice sacs from lemon. The slices were immersed in the osmotic solutions maintained with four concentrations of NaCl (5–20%, w/v) and three temperatures (30, 40, and 50°C) for predetermined time intervals (10–180?min). The sample to solution ratio was maintained at 1:10. Azuara model based on Peleg model was used to determine the equilibrium moisture loss and salt gain. Apart from the moisture loss and salt gain, it was found that the loss of solid constituents and juice sacs from the fruit into the osmotic solution was significant. Therefore, the DHC was determined to correlate the rate of solid loss. The DHC was found to be greatly affected by temperature as lemon was less capable to withhold its cell integrity at higher temperature. A combined correlation model was used to determine the effect of osmosis time, solution concentration, and temperature on moisture loss, salt gain, and solid loss. High temperature is not preferable for osmotic dehydration of lemon as it increases losses. The optimal condition was found to be 20% salt concentration and 30°C osmotic solution for 180?min to attain high moisture loss, less solid loss, and required salt uptake within allowable limits.     

SD500新型大孔吸附剂性能研究

文章研究新型大孔吸附树脂SD500对水中有机物吸附情况,并与活性炭进行比较。通过对应用前后的运行数据进行对比分析,结果显示,该大孔吸附树脂SD500对水中有机物吸附性能与活性炭相似,且能用NaCl-NaOH混合溶液再生,具有吸附容量高、去除率高、洗脱率高等优点,可以重复使用,经济性好,有很好的应用前景。