Purification of Produced Water from a Sour Oilfield in South Kuwait. 2. Oil-Water Separation and Crystallization of Calcium Carbonate

Oil-water separation for produced water (PW) originating from an oil extraction site in South Kuwait was carried out using bleached, esterified cellulosic material from used coffee grounds. Thereafter, earth-alkaline metal ions, specifically calcium ions, of the de-oiled PW were removed by precipitation with sodium carbonate to give access to pure sodium chloride as industrial salt from the remaining PW. While the purity of the precipitated calcium carbonate (CaCO3) depends on the precipitation conditions, CaCO3 of up to 95.48% purity can be obtained, which makes it a salable product. The precipitation of CaCO3 decreases the amount of calcium ions in PW from 11,300 ppm to 84 ppm.

Test for the effects of three surfactants on the penetration ability of the calcium chloride and water glass Solutions in dust

By using a downward penetration testing device, a large number of experiments were made to investigate the effects of surfactants (sodium succinate, sodium dodecyl sulfonate and dodecyl benzene sulfonic acid sodium salt) on the penetration ability of the calcium chloride and water glass solutions in four dust samples. The experimental results showed that the surfactants can enhance the penetration ability and decrease the surface tension of the calcium chloride and water glass solutions in great extent. After adding the surfactants in 0.2—0.6 wt.% to the solutions of calcium chloride and water glass in 5—25 wt.% respectively, the largest percent of penetration ability increases to 28% more. Among the three surfactants, the size of their effects on the penetration ability of calcium chloride and water solutions in the dust samples is dodecyl benzene sulfonic acid sodium salt, sodium dodecyl sulfonate and sodium succinate.The achieved conclusions are great significant for calcium chloride and water glass to be applied in the field of soil stabilization and raising dust control.

Simultaneous Determination of Calcium and Magnesium in Water Using Artificial Neural Network Spectro-Photometric Method

A new analytical method using Back-Propagation （BP） artificial neural networks and spectrophotometry for simultaneous determination of calcium and magnesium in tap water, the Yellow River water and seawater is established. By condition experiment, the optimum analytical conditions for calcium, magnesium and Arsenazo （Ⅲ） color reactions are obtained. Levenberg- Marquart （L-M） algorithm is used for calculation in BP neural network. The topological structure of three-layer BP ANN network architecture is chosen as 11-10-2 （nodes）. The initial value of gradient coefficient μ is fixed at 0.001 and the increase factor and reduction factor of kt take the default values of the system. The data are processed by computers with our own programs written in MATLAB 7.0. The relative standard deviations of the calculated results for calcium and magnesium are 2.31% and 2.14%, respectively. The results of standard addition method show that the recoveries of calcium and magnesium are 103.6% and 100.8% in the tap water, 103.2% and 96.6% in the Yellow River water （Lijin district of Shandong Province）, and 98.8%-103.3% and 98.43%-103.4% in seawater from Jiaozhou Bay of Qingdao. It is found that 14 common cations and anions do not interfere with the determination of calcium and magnesium under the optimum experimental conditions. The comparative experiments do not show any obvious differ- ence between the results obtained by this new method and those obtained by the classical complexometric titration method in seawater medium. This method exhibits good reproducibility and high accuracy in the determination of calcium and magnesium and can be used for the simultaneous determination of Ca^2＋ and Mg^2＋ in tap water and natural water.

Barium, Calcium and Sodium, Cyanide, Phosphate and Sulphate Contents of Groundwater in Some Ika Communities of Delta State, Nigeria

Barium, calcium, sodium, cyanide, phosphate and sulphate and contents of groundwater in Boji-Boji (BB) area and suburbs of Ika land, Delta State, Nigeria were studied. Groundwater is the predominant source of water for inhabitants of these communities without any form of treatment. 55 borehole water sites spread within these five sample sub-areas. The metal ions were analyzed using Solar Unicam flame Atomic Absorption Spectrophotometer. Sulphate, phosphate, and cyanide contents were determined by colorimetric method. Results indicate the presence of sodium, calcium, sulphate, and phosphate. However, barium and cyanide were below detection limit. Secondly, there was a relatively higher proportion of calcium and sulphate than sodium and phosphate in its aquifer. Thirdly, a mean ratio value of 0.018 and 0.158 was observed for the ratios of Na+/Ca2+ and ?respectively. Fourthly, sodium showed good correlation with all the other parameters. Finally, nearly all the studied parameters have concentrations below the maximum contaminant levels of the World Health Organization (WHO), invariably inferring that the water is wholesome with respect to the analytes. However, concern still remains from a health point of view on the sodium concentrations in many sample areas.

Inhibition of calcium oxalate nephrotoxicity with Zamzam water

Zamzam water is well known of its high conductivity. For this fact urologist and nephrologists recommend their patients who are suffering from kidney stones not to drink this water because it could worse their health status. This study was conducted to investigate the effect of Zamzam water on calcium oxalate nephrotoxicity in experimentally induced kidney stones in male Wistar albino rats. Calcium oxalate crystals were induced by orally administration of 200 mg of glycolic acid dissolved in the drinking water. The rats were divided into three groups;six rats each. These include positive control group (given glycolic acid), test group (given glycolic acid plus Zamzam water) and negative group (given drinking water only). After two weeks of treatment, blood analysis of blood urea nitrogen (BUN) and creatinine showed significant differences in positive control group compared to the negative control group, whereas no significant differences were noticed in the level of BUN and creatinine between both the negative control and the test group. Moreover, urine analysis showed a high density of calcium oxalate crystals in the positive control group, whereas no crystals were detected in the negative control and the test groups. Histopathological investigations showed damaging in kidneys of the positive control group with no tissue abnormalities in the negative control and the test group. I concluded from this study that Zamzam water prevents the formation calcium oxalate stone, which probably mean that it has no negative effect on patients suffering from kidney disorders due to crystals formation.

Unsaturated transport properties of water molecules and ions in graphene oxide/hydrated calcium silicate nanochannels:from basic principles to complex environmental performance effects

The problems of traditional concrete such as brittleness,poor toughness and short service life of concrete engineering under acid rain or marine environment need to be solved urgently.Hydrated calcium silicate(C-S-H)is a key component to improve the mechanical properties and durability of concrete.However,the traditional method of concrete material design based on empirical models or comparative tests has become a bottleneck restricting the sustainable development of concrete.The synthesis method,molecular structure and properties of C-S-H were systematically described in this paper;The interface structure and interaction of graphene oxide/calcium silicate hydrate(C-S-H/GO)were discussed.On this basis,the saturated and unsaturated transport characteristics of ions and water molecules in C-S-H/GO nanochannels under the environment of ocean and acid rain were introduced.The contents of this review provide the basis for improving the multi-scale transmission theory and microstructure design of concrete.It has important guiding significance for analyzing and improving the service life of concrete in complex environment.

超声强化EDTA二钠对硫酸钙垢的溶解效果及其机理

为掌握超声预处理EDTA二钠对硫酸钙垢溶解效果的影响规律,开展了超声预处理EDTA二钠溶液溶解硫酸钙垢试验。采用XRD、FTIR等手段分别对垢体和EDTA二钠溶液进行了分析,结果表明:在超声功率为168 W时,硫酸钙垢溶解率最高,达57.40%,溶液电导率为20.10 mS/cm,较未处理时的硫酸钙垢溶解率提高了10.40百分点;超声预处理可使EDTA二钠溶液中亲水性的缔合水羟基及乙二胺四乙酸根的羟基含量升高,促进垢体表面的活性点钙离子的水合作用,吸附水进入垢体内部,使其体积膨胀;溶液中的乙二胺四乙酸根离子可与垢体表面钙离子生成钙盐络合物,促进垢体表面的钙离子向溶液中迁移及垢体溶解。

Early calcium monocarboaluminate hydrate formation in cement paste:effect of polycarboxylate type admixture

Effects of polycarboxylate type admixture（PCA）on calcium monocarboaluminate hydrate（AFmc）formation in hydrated cement paste containing limestone filler（LF）are investigated by the Fourier transform infrared spectroscopy（FTIR）,the scanning electron microscopy（SEM）,the derivative thermogravimetric（DTG）analysis and the adsorption amount measurement.Experimental results indicate that AFmc forms during the initial hydration period of cement as early as 15 min.It is found that PCA accelerates the early age AFmc formation and enhances cement hydration by promoting C4AF hydration at the early age,and,as a consequence,the iron associated AFmc phase forms more readily.The phenomenon is not observed when PCA is replaced by a naphthalene formaldehyde sulphonate condensate water reducer.Compatibility between PCA and cement is modified due to the presence of AFmc along with ettringite（AFt）,which results in a less adsorption amount of PCA on the surface of cement minerals.As a kind of high-range water reducer,PCA may be the preferred choice for concrete containing LF.

掺硫铝酸钙类膨胀剂白水泥净浆干燥收缩与水分损失关联

为精确解析干燥条件下掺硫铝酸钙类膨胀剂水泥基材料的收缩行为,深入揭示低相对湿度条件下硫铝酸钙类膨胀剂补偿收缩效果下降的机制,利用低场磁共振弛豫技术,结合X射线衍射、质量与长度测试,在不同相对湿度下对掺与不掺硫铝酸钙类膨胀剂白水泥净浆的干燥收缩历程进行10个月的长期监测,从含水量及水分状态角度,定量描述白水泥净浆干燥失水和收缩的演变规律,阐明硫铝酸钙类膨胀剂导致干燥收缩落差增大的作用机制。结果表明:在相对湿度为75%、43%、11%的环境中干燥,白水泥净浆失水量和干燥收缩均持续增大直至稳定,3类环境中各试件干燥收缩与相对失水量间的关系基本保持一致;随干燥时间延长,单位失水量导致的干燥收缩先降低后升高,干燥进程中净浆内部各级孔隙失水规律不同,且各湿度条件下的干燥收缩机制存在差异;掺入硫铝酸钙类膨胀剂后,C-S-H凝胶纳米孔结构会发生一定粗化,干燥时易损失更多可蒸发水,且膨胀剂水化生成的钙矾石还会损失2~5个结晶水,二者共同导致净浆水分损失与干燥收缩增大;在低湿度环境中应用硫铝酸钙类膨胀剂时,需注意这两个因素导致收缩落差增大的影响。

高矿化度矿井水热法脱盐过程中硫酸钙的结垢趋势预测及验证

高矿化度矿井水具有成分复杂、含盐量高、硬度大的特点,在热法脱盐过程中会产生以CaSO_(4)为主的无机垢。根据高矿化度矿井水的典型组成,配制含有Ca^(2+)-Mg^(2+)-Na^(+)-Cl^(-)-SO_(4)^(2-)的模拟原料液,首先采用恒温溶解法,考察温度为40、50、60、70℃时CaSO_(4)在Ca^(2+)-Mg^(2+)-Na^(+)-Cl^(-)-SO_(4)^(2-)体系的溶解度。结果表明:在40~70℃的范围内,CaSO_(4)的溶解度随温度的升高而减小,随MgCl_(2)浓度的增加而增大,随Na_(2)SO_(4)浓度的增加而减小。采用Oddo-Tomson饱和指数法,对CaSO_(4)在热法脱盐过程的结垢趋势进行预测,得到修正的饱和指数(SI)方程,该方程预测结果与65℃下CaSO_(4)在不锈钢管表面的结垢实验相吻合。且当饱和指数大于0.2时,Ca^(2+)-Mg^(2+)-Na^(+)-Cl^(-)-SO_(4)^(2-)体系中的CaSO_(4)晶体开始在不锈钢管表面析出,最后采用模拟高矿化度矿井水SA和SB的结垢实验说明本方法在实际矿井水应用的可行性和局限性。

Environmental Problems From Tea Cultivation in Japan and a Control Measure Using Calcium Cyanamide

A field experiment, involving lime N (calcium cyanamide, CaCN2) fertilization as a control measure, was conducted to study environmental problems induced by long-term heavy N application in Japanese tea fields. Long-term tea cultivation caused serious soil acidification. Seventy-seven percent of the 70 tea fields investigated had soil pH values below 4.0, and 9% below 3.0, with the lowest value of 2.7. Moreover, excess N application in tea fields put a threat to plant growth, induced serious nitrate contamination to local water, and caused high nitrous oxide loss. Compared with the conventional high N application treatment (1100 kg N ha-1) without lime N, the low N application (400 kg N ha-1) with calcium cyanamide effectively stopped soil acidification as well as achieved the same or slightly higher levels in tea yield and in total N and amino acid contents of tea shoots. The application of calcium cyanamide could be a suitable fertilization for the prevention of environmental problems in tea cultivation.

Laparoscopic treatment of a calcium fluorophosphate stone within a seminal vesicle cyst

Stones in the seminal vesicles are extremely rare. We present a 62-year-old patient with a stone within a seminal vesicle cyst, who was cured by laparoscopic treatment. The operative time was 80 rnin, and the estimated blood loss was 90 mL. Scanning electron microscope examination of the stone showed a compact crystal image externally and sparse spherical crystal structure in kernel. Composition of the stone was calcium fluorophosphate on X-ray diffractometer. The follow-up time was 15 months with no recurrence of cyst or stone. To our knowledge, this case is the first to describe laparoscopic removal of a stone within a seminal vesicle cyst, and the first to describe calcium fluorophosphate as the composition of seminal vesicle stones. （Asian JAndro12008 Mar; 10： 337-340）

Interaction of ions in water system containing copper-zinc alloy for boiler energy saving

Copper-zinc alloy element for boiler energy saving was put in the intake of simulated boiler system to investigate the interaction and transfer of ions in water system both theoretically and experimentally.The fouling was analyzed by scanning electron microscopy(SEM)and energy dispersive X-ray detector(EDX).The results show that the transfer of calcium and magnesium ions in heat-transfer-surface-water system is affected by zinc ions dissolved from the alloy because of primary battery reaction.Some calcium ions of calcium carbonate crystal are replaced by zinc ions,the growth of aragonite crystal nucleus is retarded,and the transition of calcium carbonate from aragonite to calcite is hampered.

Contribution to the Study of Hot Water Scaling Phenomenon in the South of Touristic Area in Agadir City

This work aims to study the phenomenon of scaling observed in the hot water pipelines in the southern seaside touristic installations of Agadir city. This phenomenon has led to the formation of solid deposits and adherents to the internal walls of the facilities of the hot water. This deposit is at the origin of several technical, economic and environmental problems. It causes a decrease in the lifetime of boilers and a reduction of thermal exchanges and consequently a decrease in the energy efficiency of heating systems. In the present study, the samples of scale have been carried out at different points of hot water pipelines. The characterization of different scale samples recovered was conducted by X-ray fluorescence (XRF), elemental analysis (CHNS-O), infrared spectrometry (IR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Analytical results showed that scale samples collected on different sites in touristic hot water system are mostly formed by calcium carbonate. Thermodynamic conditions in the site were favourable to the aragonite variety formation.

Effects of the partial replacement of La by M(M=Ce,Ca and Sr) in La_(2-x)M_xCuO_4 perovskites on catalysis of the water-gas shift reaction

The performance of La2-x M x CuO4 perovskites （where M=Ce,Ca or Sr） as catalysts for the water-gas shift reaction was investigated at 290℃ and 360℃.The catalysts were characterized by EDS,XRD,N2 adsorption-desorption,XPS and XANES.The XRD results showed that all the perovskites exhibited a single phase （the presence of perovskite structure）,suggesting the incorporation of metals in the perovskite structure.The XPS and XANES results showed the presence of Cu2＋ on the surface.The perovskites that exhibited the best catalytic performance were La 2 x Ce x CuO 4 perovskites,with CO conversions of 85% 90%.Moreover,these perovskites have higher surface areas and larger amounts of Cu on the surface.And Ce has a higher filled energy level than the other metals,increasing the energy of the valence band of Ce and providing more electrons for the reaction.Besides,the La1.80Ca0.20CuO4 perovskite showed a good catalytic performance.

Leaf water potential and gas exchange of eucalypt clonal seedlings to leaf solar protectant

This experiment was carried out in acclimatized greenhouses with seedlings of two hybrid clones of Eucalyptus urophylla×Eucalyptus grandis. A sunscreen protector consisting of 62.5% calcium carbonate was sprayed on the seedlings at weekly intervals. Water stress was induced by suspending irrigation until the soil reached 30% available water and water was then replaced so that it returned to field capacity. Gas exchange and leaf water status were measured after 50 days. The experiment was set up in a 4×2 factorial randomized block design in four distinct environments:(1) temperatures less than 21.2℃ and vapor pressure deficit of 0.15 kPa;(2) intermediate temperatures of 24.2℃ and vapor pressure deficit of 0.69 kPa;(3) high temperatures of 27.0℃ and high vapor pressure deficit of 1.4 kPa; and,(4) high temperature of 27.0℃ and vapor pressure deficit below 1.10 kPa. Two leaf sun protector treatments were used, with five replications each. High atmospheric demand acted as a stress factor for the seedlings during the initial growth phase.Applications of leaf sunscreen protector provided beneficial effects in maintaining optimum water status and gas exchanges of the plants under water stress.

Research on Preparation and Influencing Fctors of High Calcium High Sulfate Ash to Autoclaved Aerated Concrete

In this paper, a high calcium high sulfate ash as the main material, adding fly ash, lime, cement, gypsum and some modifiers to prepare autoclaved aerated concrete. The products complies with the technical requirements of GB/T11968-2006. This paper also studies the influence of the physical methods and water ratio on autoclaved aerated concrete by high calcium high sulfate ash aerated concrete. The best ratio of water and Grinding time were found in practice study.

Study of the Inhibitor Scaling Effect of the Agricultural Water by a Phosphate Fertilizer

The localised irrigation or drop by drop system is a technique which makes it possible to save water, because it ensures a balanced and efficient distribution of water and an effective fertilization. However, this ferti-irrigation system is facing a number of problems hindering the agricultural development. The lack of uniformity of the localised irrigation was observed and found out that it is due to chemical clogging of drippers. Considering the complexity of the composition of the natural water used in micro-irrigation, we started our study by examining the effectiveness of the inhibitor on pure calco-carbonic water with 40°F, and then moved to explore the natural water of the agricultural region. The Legrand-Poirier-Leroy method allowed us to determine the position of the irrigation water compared to calco-carbonic balance. LCGE (abbreviation of “Laboratory of Chemistry and Environmental Engineering”) technique, based on the accelerated formation of calcium carbonate deposit under the effect of a degasification of studied water, enabled us to evaluate the scaling power of this water of irrigation either with or without inhibitor. The experimental results showed the following: in the case of pure calco-carbonic water with 40?F and of natural water, the addition respectively of 2 mg/L and 2.25 mg/L of phosphate fertilizer completely inhibits the precipitation of calcium carbonate under the conditions of the experiment.

Characterization of Scale Formed in Drinking Water and Hot Water Pipes in the Taliouine Downtown—Morocco

This paper presents the results of a comprehensive study of water scale found in water distribution system of Taliouine city in the south of Morocco. Physico-chemical properties of drinking water supplied to the city were evaluated. The data showed a high level of soluble salt in water. Concentrations were calcium 108 - 143 mg/1, magnesium 80 - 96 mg/1, bicarbonate 660 - 750 mg/l and hardness degree 660 - 690 mg CaCO3/l. The water samples contain high amounts of minerals in the form of ions, especially the metals calcium and bicarbonate, which precipitated out and caused problems in water conducting or storing vessels like pipes. Scales were removed from the inside of two old pipes which transported drinking and hot water in the downtown of Taliouine city. Scale samples were investigated by XRF, XRD, SEM, DTA, TGA and SEM’s analytical techniques. This study was able to identify scales formed in pipes of water distribution systems. It was found that water scale in this city contains 53% of calcium oxide and 43% of organic matter. The XRD and SEM results revealed that calcite was the main crystalline structure in drinking water scale. Nevertheless, scale deposited in hot water pipe is well crystalline with peaks corresponding mostly to aragonite (88%) along with calcite (12%). The thermal behavior of scale samples confirms that calcium carbonate was the main compound in the scale samples. Further studies are needed to find an efficient antiscale in drinking water of this city.

Effects of Calcium Ions on Thermodynamic Properties of Mixed Bilirubin/Cholesterol Monolayers

The mixed monolayer behavior of bilirubin/cholesterol was studied through surface pressure-area （π-A） isotherms on aqueous solutions containing various concentrations of calcium ions. Based on the data of π-A isotherms, the mean area per molecule, collapse pressure, surface compressibility modulus, excess molecular areas, free energy of mixing, and excess free energy of mixing of the monolayers on different subphases were calculated. The results show an expansion in the structure of the mixed monolayer with Ca^2＋ in subphase, and non-ideal mixing of the components at the air/water interface is observed with positive deviation from the additivity rule in the excess molecular areas. The miscibility between the components is weakened with the increase of concentration of Ca^2＋ in subphase. The facts indicate the presence of coordination between Ca^2＋ and the two components. The mixed monolayer, in which the molar ratio of bilirubin to cholesterol is 3：2, is more stable from a thermodynamic point of view on pure water. But the stable 3：2 stoichiometry complex is destroyed with the increase of the concentration of Ca^2＋ in subphase. Otherwise, the mixed monolayers have more thermodynamic stability at lower surface pressure on Ca^2＋ subphase.