斜发沸石脱除饮用水中氟的性能研究

利用天然斜发沸石岩脱除饮用水中氟的研究和应用，国内只是近十多年的事，其除氟机理目前仍处于探讨阶段，一般认为^[1]，斜发沸石岩先用稀碱液活化，再用明矾溶液浸泡即具有除氟作用，然而，我们用某地沸石岩进行饮用水除氟的试验过程中发现，有的沸石没有除氟效果，有的高品位沸石反比低品位沸石除氟效果差，为了查明原因，我们用不同产地的沸石样作了对比试验，在归纳试验事实的基础上，对沸石除氟机理进行了进一步探讨，并改善了沸石除氟工艺。     

我国斜发沸石、丝光沸石的阳离子类型和硅铝比

 本文根据大量样品数据,提出划分沸石离子类型的主、次阳离子原则和单离子类型原则。进而对我国几十个矿点的大量随机样品进行分类,结果形成Ca、K、Na三个系列,K-Ca.Ca-K等12种离子类型。同时弄清了我国沸石的特点是以各种Ca型为主,以各种K型居其次。     

碱处理对河北围场天然沸石结构和性能的影响及其机理研究

采用NaOH对围场地区天然沸石进行处理,采用X射线衍射仪、红外光谱仪、N2吸附-脱附技术、扫描电子显微镜等对材料进行表征分析,采用水蒸气吸附法评价材料的亲水性,采用Cr3+和Mn2+评价材料的离子交换性能,探讨了碱处理对天然沸石的结构、亲水性和离子交换性能的影响及其机理.实验结果表明,围场地区天然沸石中主要含有斜发沸石...     

高氟地下水混凝沉淀降氟试验研究

本文开展了山西运城地区高氟地下水的降氟试验,对聚铁、硫酸铝和明矾等不同混凝剂降氟效果进行对比,探讨了地下水硬度对混凝沉淀除氟效果的影响.实验结果表明:明矾混凝沉降效果优于其它混凝剂,0.3g/L的明矾溶液可使含氟浓度4.0mg/L 的地下水降低到浓度1.0mg/L以下;地下水的硬度对明矾混凝降氟效果没有明显影响.     

改性蒙脱石吸附水中氟离子的实验研究

制备四种改性蒙脱石，并利用X射线衍射分布和化学成分分析方法对其进行了表征，选用其中两种对水中的氟离子进行了吸附试验，通过正交实验确定了它们吸附氟离子的适宜条件及吸附等温线（25℃）。结果表明，制备的改性蒙脱石具有很强的吸附氟离子的能力，在pH分别为5和4时的除氟效果最好，吸附等温线符合Freundlich型吸附等温线方程。     

我国饮用水除砷氟技术研究现状

饮用水砷、氟超标是影响我国农村饮水安全的主要问题之一,近年来我国饮用水除砷、除氟的技术发展迅速,对我国饮用水除砷、氟技术现状进行总结。分别阐述各种技术方法的特点和优劣势。     

酸改性红辉沸石特征研究

采用物理比表面积、扫描电镜、红外光谱、X射线衍射、差热等方法来表征酸改性后的红辉沸石矿石特征,获得通过酸改性后红辉沸石比表面积、孔容和原矿中的杂质都会发生变化,从而可提高红辉沸石的吸附和交换性能,达到改性红辉沸石处理污染物的能力。     

改性红辉沸石去除水溶液中氨氮的初步研究

文章研究了采用酸、碱、盐改性红辉沸石和加热活化红辉沸石对改性红辉沸石去除水溶液中氨氮的影响效果。实验结果表明：（1）用红辉沸石去除溶液中氨氮的实验条件选择如下：1搅拌时间为30min;2沸石粒度为40～60目;3沸石用量为2g;4氯化氨溶液浓度为40mg/L;5氯化氨溶液用量为80ml。（2）采用高温活化对提高红辉沸石去除氨氮效率的作用不明显。（3）酸和碱改性对提高红辉沸石去除氨氮的效率有一定的作用,其中盐酸改性的红辉沸石去除氨氮效率为16.2%,硫酸改性的红辉沸石去除氨氮效率为13.1%,碱改性的红辉沸石去除氨氮效率为25.6%。（4）盐改性对红辉沸石去除水溶液中氨氮的影响效果巨大：经盐改性后,去除率由9.6%升高至72.6%。     

沸石的改性及其对水源水中氨氮去除的研究

以水源水为处理对象,通过对沸石进行酸、盐、高温改性和氨氮去除试验,考察沸石粒径、接触时间、温度等因素对氨氮去除的影响。结果表明,经盐(NaCl)改性的沸石对氨氮有较高的去除率,对于氨氮浓度为4.43mg/L的水源水,在粒径0.8～1.7mm、温度25℃的条件下,经15min接触,氨氮浓度可降至0.3mg/L,去除率可达93.2%。改性沸石对氨氮的去除机理是沸石表面(及内部孔隙)吸附作用和离子交换作用。对于普通自来水厂,只需将快滤池中常用的石英砂部分替换成改性沸石即可有效去除饮用水中的氨氮。经测算其投资仅增加33～39元/m3,运行费用基本不变。     

改性沸石对重金属离子竞争吸附特性研究

以钠型改性沸石为吸附剂,以含有单一的镉、锌、铅溶液以及镉、锌、铅的混合溶液为吸附质,开展了改性沸石中重金属离子的竞争吸附及其影响因素等实验研究。结果表明,当溶液中有多种二价重金属离子存在时,各离子之间存在竞争吸附,竞争能力为Pb2+>Cd2+>Zn2+;Zn2+-Cd2+表现出显著的协同吸附效应,而Zn2+-Pb2+、Cd2+-Pb2+表现出拮抗吸附。     

An experimental study on the process of zeolite formation

Results are reported of an experimental study which examined the effect of solution composition on the composition, structure, and crystallization path of phillipsite and merlinoite in the system Na₂OK₂O-Al₂O₃-SiO₂H₂O at 80°C and $\text{pH = 13.34–13.71}$.At a fixed 3.5 M total dissolved silica concentration, zeolite Si/Al ratio was found to be a linear function of pH within the pH range of the experiments.²⁹Si NMR spectra of the initial solutions show that pH determines the distribution of aqueous aluminosilicate species and, as a result, the precipitated zeolite Si/Al ratio. SEM observations reveal that zeolites may precipitate with or without the presence of an intermediary gel phase, depending on solution composition. The growth rate of the zeolites was found to be dependent upon solution pH and total dissolved aluminum concentration. These observations are discussed in terms of their possible applications to natural zeolite paragenesis and serve to delineate the framework of a comprehensive theory for the mechanism of zeolite crystallization from highly alkaline solutions.     

滹沱河地区地下水适宜水位研究

滹沱河流域地下水长期无节制开采造成部分浅层含水层处于疏干或半疏干状态,在分析地下开采现状基础上,根据区内垃圾填埋场和重要构筑物分布等情况,采用综合评价方法确定地下水适宜水位上、下限划定的原则,最终给出了基于环境、工程等多限制条件下的地下水适宜水位,采用mapgis网格剖分和叠加技术对滹沱河流域地下水流场进行处理,计算出滹沱河地区地下水可调控库容空间为91.48 × 108m3.为石家庄地区南水北调实施前后地下水调控方案、地下水可持续开发利用提供理论依据.     

中国北方高氟地下水分布特征和成因分析

在中国北方地区,由于饮用高氟地下水而导致的地方病,严重影响了当地人民群众的身体健康。地下水中氟元素的富集是一个非常复杂的水文地球化学过程。本文在前人研究中国北方高氟水分布特征基础上,总结了高氟水形成的气候、水文、地质构造、岩性与土壤、水文地质条件和水化学特征,并结合项目成果提出高氟水地区适宜找水模式和一些去除水中氟元素有效的措施,从而避免氟中毒的发生。     

Spectroscopic study of heavy metals sorption on clinoptilolite

Sorption of heavy metal cations (Pb(II), Cr(III), Cd(II), Ni(II)) from aqueous solutions on natural Na-clinoptilolite was studied using atomic absorption spectrometry (AAS) and FT-IR spectroscopy. It was found that the sorption capacity of clinoptilolite decreases in the following order: Pb(II) (22,600 mg/kg), Cr(III) (21,200 mg/kg), Cd(II) (10,400 mg/kg) and Ni(II) (6,200 mg/kg). In the FT-IR spectra of the samples, in the region of pseudolattice vibrations (500–800 cm^–1), systematic changes connected with the type of cation and its concentration in the initial solution were observed. The proportions of ion exchange and chemisorption in the whole process of sorption were also estimated. It was found that the amount of cations sorbed on clinoptilolite depended on the concentrations and pH of the solutions used as well as on the contact time of zeolite-solution system. After 120 min of the reaction, despite the metal type, 90–100% of the total amount of cations were immobilized.     

Modelling the response of vegetation restoration to changes in groundwater level,based on ecologically suitable groundwater depth

Groundwater-level fluctuations at a large scale have a significant effect on the preservation and restoration of vegetation. This study determined suitable groundwater depth within which natural vegetation grows well, and analysed the effect of groundwater regulation on vegetation restoration in Tianjin City, northern China. Normal and lognormal distributions were used to fit the curve of the relation between vegetation and groundwater depth. The groundwater depth range corresponding to the higher frequency of vegetation distribution was regarded as the ‘suitable water depth’ range for vegetation growth. The suitable groundwater depth for shrub growth was 3–5 m and for grass growth 1–3 m. A groundwater flow model predicted the future changes of groundwater depths in the vegetation distribution area under the condition that the current levels of groundwater extraction are maintained. The results showed that there is potential for the extraction of groundwater in shrubland areas, but for grassland areas the water-table elevation showed a downward trend, meaning that water shortages in some areas may be more severe in the future. Finally, based on the current groundwater extraction regime, two regulation schemes were developed: (1) for shrubland, groundwater extraction was reduced by 10% in the ecological water deficit areas, and extraction was increased by 10% in the ecological water surplus and suitable areas, and (2) for grassland, groundwater recharge was increased by the restoration of the wetland areas. In conclusion, the groundwater depths in most of the area would be more suitable for vegetation growth under the regulation schemes.     

An experimental study into the geometry of supply-limited dunes

The relationship between dune geometry and the volume of mobile sediment was studied in flume experiments. In these flume experiments, the volume of mobile sediment on top of an immobile coarse sediment layer was increased stepwise and the bedform characteristics were observed. A strong relationship was found between the volume that is mobile – and therefore available for bedform formation – and the dune dimensions and regularity. If the sediment supply is limited, dunes are smaller and more regular. Series of experiments with a decreasing supply limitation were conducted for different flow velocities and water depths. The relationship between the dune dimensions and the available volume is different for each series. The observed relationships between dune dimensions and layer thickness collapse to one relationship for height and one for length if scaling parameters are introduced. Current models for bedform dimensions under alluvial conditions can be extended to partial transport conditions using this relationship.     

An experimental study on the micromechanical behavior of pumice

Acta Geotechnica - Pumice has a large potential to be used in structural and geotechnical engineering projects as a lightweight aggregate, and it is a material of unique characteristics....     

水中腐植酸现场快速检测方法实验研究

饮用水中的微量腐植酸能与重金属形成稳定的络合物,从而对水体中重金属的存在形态、迁移转化起着重大的作用,因此测定水中腐植酸的含量对评价地质环境与地方病的关系有着重要意义。实验室中检测腐植酸的方法很多,但绝大多数不适合野外快速检测应用。在综合分析实验室各种检测方法优缺点的基础上,提出了用比色法快速检测水中腐植酸。在实验室中用Ports-15光谱仪,2cm、5cm光纤比色探头,650nm波长的红光,分别对该方法进行测试,给出了腐植酸浓度与吸光度关系曲线,确定该方法的最低检出限、重复度和合适光程的比色探头。