Purification of starch and phosphorus wastewater using core-shell magnetic seeds prepared by sulfated roasting

Core-shell magnetic seeds with certain adsorption capacity that were prepared by sulfated roasting, served as the core of a magnetic separation technology for purification of starch wastewater. XRD and SEM results indicate that magnetite's surface transformed to be porous α-Fe_2O_3 structure. Compared with magnetite particles, the specific surface area was significantly improved to be 8.361 from 2.591 m~2/g, with little decrease in specific susceptibility. Zeta potential, FT-IR and XPS experiments indicate that both phosphate and starch adsorbed on the surface of the core-shell magnetic seeds by chemical adsorption, which fits well with the Langmuir adsorption model. The porous surface structure of magnetic seeds significantly contributes to the adsorption of phosphate and starch species, which can be efficiently removed to be 1.51 mg/L(phosphate) and 9.51 mg/L(starch) using magnetic separation.     

Using Multi-destination ZTCM to Evaluate the Recreational Values of Cultural Sights: An Application to Jiayuguan,China

Abstract

This study explained the importance of environmental protection in tourism development and illustrated the relationship between recreational resource valuation and environmental consideration. We compare different models of travel cost method and reiterates long-time existing problems of multi-destination and treats of time opportunity cost (TOC). Taking Jiayuguan’s cultural sights as an example, we establish an updated method called multidestination zonal tourism cost method to evaluate the recreational values (RVs) of selected three cultural sights. We divide trip packages of Jiayuguan’s tourists into 11 portfolios. Each portfolio can be seen as a separate commodity, and each commodity has its own demand curve. According to demand curves we can calculate consumer surplus (CS) of different portfolios of tourist destinations and later we sum up the total travel costs (including travel expenditure and TOC) and CS to come to the RVs of each portfolio. We then apply suitable proportions to calculate the RVs between different destinations in the portfolio. In the end, we add up all the RVs calculated for the objective destination. Using this method, we draw conclusions that Jiayuguan’s RV in 2006 includes national and international values, summing up to 738.4762 million yuan. The tourist expenditure, CS and TOC of Jiayuguan is proportionating 62.96, 32.28 and 4.76%, respectively. This study is also an example of non-market valuation of cultural tourism resources.     

Numerical simulation of flue gas desulfurization characteristics in CFB with bypass ducts

A new process of flue gas desulfurization in circulating fluidized bed with flue gas bypass ducts is presented. k–? Model, Discrete Phase Model and Finite-Rate Chemistry Model are proposed to simulate the desulfurization process characteristics in circulating fluidized bed reactor. The proposed model is validated by the comparison of experimental data and simulation results. The results show that the desulfurization reactor with bypass ducts is superior to the reactor without bypass ducts. The reactor with bypass ducts has higher desulfurization efficiencies and lower flow resistances than the reactor without bypass ducts, and it is more suitable for flue gas flow variation. Desulfurization reaction rate is controlled by absorption reaction on sorbent particles surface. When water content and Ca/S ratio increase, desulfurization efficiency of the reactor with bypass ducts increases. When SO₂ concentration increases, desulfurization efficiency decreases.     

酸雨及大气颗粒物中可溶性SO_4~(2-)的流动注射—比浊法测定

本文研究了在一定酸度下,以BaCl_2为沉淀剂,OP(聚乙二醇辛基苯基醚)为保护剂的比浊法测定酸雨及大气颗粒物中SO_4~(2-)含量的分析条件,选择的最佳体系为:BaCl_2·2H_2O(2％)—OP(5％)。SO_4~(2-)含量在0.6—7.2μg1ml范围内呈线性关系,回收率为95～105％,相对平均标准偏差小于2.6％。在此基础上与流动注射仪联用,提高了分析速度,改善了精密度。     

慈禧与消防

慈槽对外屈辱和对内施以高压政策残酷镇压人民起义的反动行径,尽人皆知。然而,在其垂帘听政时期有关消防事宜,却鲜为人知。仅述一二,以飨读者。光绪年间,始设消防队光绪三十一年(1905年)曾经担任过外务尚书的袁世凯对日本的警察制度颇感兴趣,他给慈禧太后和光绪皇帝递过一个奏折,内称:“外国警察之制上通政府,下达穷乡,建立警察制度对于推进新政有事半功倍者。”慈禧太后和     

樟脑和龙脑等萜类化合物废水处理工艺

采用隔油－混凝－气浮－厌氧－好氧组合工艺处理某化工厂樟脑、龙脑等萜类化合物废水，对处理装置运行的主要影响因素进行了分析研究并对运行难点提出了解决途径。运行结果表明，该工艺对含高浓度硫酸根的萜类化合物生产废水的处理效果很好，出水COD在86mg/L以内，低于广州污水排放标准。     

绿色贸易壁垒与环境保护

通过对绿色贸易壁垒的发展、种类以及绿色贸易壁垒与环境保护的关系等理论方面的论述，分析了我国面临的绿色贸易壁垒的主要问题及原因，提出了应对的基本策略。     

描述北方河流封冻期BOD-DO动态的数学模型

本文定量地研究了北方河流封冻期BOD-DO的动态变化规律。提出了一种描述这一动态变化规律的数学模型形式,并且根据在图们江上收集到的实测数据,利用参数估计方法确定了模型中的耗氧系数K_1、复氧系数K_2和BOD沉淀-再悬浮系数K_3.通过实测数据对该模型进行检验的结果证明,它能较好地反映封冻期河流中的BOD-DO动态,可以做为这一时期水质预测与控制的基础。 用数学模型来描述封冻期河流中BOD-DO的变化规律尚属初次,所提出的模型结构形式仍有待于进一步完善。     

低温等离子体技术及其治理工业废气的应用

利用低温等离子体技术对低浓度、高流速、大风量的含挥发性有机污染物和含硫类污染物等工业废气进行处理，实验室结果为介质阻挡放电产生的低温等离子体分解污染物效果好。在化纤厂对含硫工业废气做了实际应用的示范工程，中试装置已连续稳定运行１０００ｈ以上。     

民国初年灾荒史研究综述

自民国迄今，一些政治家、思想家及学者分别从自然科学角度和社会历史角度对民国初年灾荒史予以诠释，依时间而言主要集中于20世纪80年代以后，依内容而言又呈现出一种多元化的态势．其间，虽然取得了一定的成就，诸如积累了一些资料、研究内容多样化等，但仍存在着一些不足。