改性纤维球在油田污水处理中的应用

纤维球过滤可充分发挥出滤料深层的截污能力。介绍了改性纤维球滤料的技术要求,在使用过程中主要存在的几个问题,改性纤维球过滤器的结构及特点,在油田污水处理中的现场应用情况。试验证明,经50%互溶剂+2%表面活性剂+2%烧碱清洗后,改性纤维球滤料颜色变为灰白,纤维之间松散,不存在粘结现象,清洗较为彻底。     

Cobalt and zinc removal from aqueous solution by chemically treated bentonite

Natural bentonite was treated by hydrochloric, nitric, and phosphoric acids followed by washing with sodium hydroxide in order to enhance its adsorption capacity. The sample that treated with hydrochloric acid followed by further treatment with NaOH showed the highest cation exchange capacity with a value of 51.20 meq/100 g. The zero-point of charge for this sample was found to be 4.50. Adsorption isotherms for both cobalt and zinc were fitted using Langmuir, Freundlich, and Redlich-Peterson and showed an adsorption capacity of 138.1 mg Co²⁺ and 202.6 mg Zn²⁺ per gram of treated sample.     

Evaluation of soils for use as liner materials: a soil chemistry approach

Movement of NH(4)(+) below animal waste lagoons is generally a function of the whole-lagoon seepage rate, soil mineralogy, cations in the lagoon liquor, and selectivity for NH(4)(+) on the soil-exchange sites. Binary exchange reactions (Ca(2+)-K(+), Ca(2+)-NH(4)(+), and K(+)-NH(4)(+)) were conducted on two soils from the Great Plains and with combinations of these soils with bentonite or zeolite added. Binary exchanges were used to predict ternary exchanges Ca(2+)-K(+)-NH(4)(+) following the Rothmund-Kornfeld approach and Gaines-Thomas convention. Potassium and NH(4)(+) were preferred over Ca(2+), and K(+) was preferred over NH(4)(+) in all soils and soils with amendments. Generally, the addition of bentonite did not change cation selectivity over the native soils, whereas the addition of zeolite did. The Rothmund-Kornfeld approach worked well for predicting equivalent fractions of cations on the exchanger phase when only ternary-solution phase compositions were known. Actual swine- and cattle-lagoon solution compositions and the Rothmund-Kornfeld approach were used to project that native soils are predicted to retain 53 and 23%, respectively, of the downward-moving NH(4)(+) on their exchange sites. Additions of bentonite or zeolite to soils under swine lagoons may only slightly improve the equivalent fraction of NH(4)(+) on the exchange sites. Although additions of bentonite or zeolite may not help increase the NH(4)(+) selectivity of a liner material, increases in the overall cation exchange capacity (CEC) of a soil will ultimately decrease the amount of soil needed to adsorb downward-moving NH(4)(+).     

Removal and recycling of copper from aqueous solutions using treated Indian barks

Removal of copper from aqueous solutions containing 100–1000 ppm, using different Indian bark species, was performed on laboratory scale. The percentage removal of metal ions depends on the solution pH, bark species and time. The efficiency of copper removal by the used raw barks increases with a rise of solution pH and reaches a maximum of about 65–78% around pH 4–5. However, the decontaminated aqueous solutions were colored due to the dissolution of soluble organic compounds contained in the raw bark. This increases the biological and chemical oxygen demand (BOD and COD) of the solutions as well as the total organic carbon content (TOC). For this reason, raw bark should be treated either by chemical or biological means. Such treatment will allow the extraction of the soluble organic compounds and increase the chelating capacity and efficiency of the treated bark. Depending on the pH value, the chelating efficiency of treated barks is about 1.2–2.2 times that of the raw ones. Moreover, the retention capacity of the Indian treated bark varies from about 42–51 mg/g of dry bark. It is equal to or higher than that of common European species. About 1.8 mols of H₃O⁺ are released, by the treated barks, for every mol of chelated copper ions. Moreover, scanning electron microscopy (SEM) observations show uniform distribution of metal ions throughout the copper saturated bark. Infra red (IR) spectra suggest that the copper ions are chelated to hydroxyl and/or carboxyl functional groups of organic compounds contained in the treated bark. It seems that the interaction of the copper ions with the bark follows a cation exchange mechanism. This hypothesis is supported by elution experiments that allow recovery of about 99% of the contained copper. The retention capacity of the treated bark is almost constant after five cycles of chelation–elution, suggesting that the ‘life time cycle' is sufficiently long for continuous industrial application. The spent copper loaded barks can either be incinerated or pyrolysed. It generates solids containing either ≈80% of CuO or ≈14% of Cu°, respectively. Such materials can be used either in the secondary or primary copper production, thus offering a friendly environmental solution of effluents' treatment. The suggested process can be used as an alternative to the classical technologies for effluent decontamination. It is also efficient for polishing effluents treated by other methods.     

炼油厂含硫污水处理副产品──氨水的综合利用

通过叙述炼油厂常减压装置“三顶”、催化裂化装置分馏塔顶注入氨水以代替烧碱的工艺流程、操作条件。并结合数据分析说明注氨后对油品质量、设备防腐所起到的效果。说明该项技术合理、安全可靠。同时阐述了该项“三废”处理及环保技术的综合利用价值,给企业带来一定的经济效益和环境效益。     

我国沸石去除水中氨氮的现状研究

沸石是一种天然、有效、价廉的环境友好型材料,其对氨氮具有很强的选择吸附性。本文就国内在沸石去除水中氨氮的机理、影响因素、沸石的改性及沸石研究的发展等方面进行广泛探讨。阐述了国内沸石去除水中氨氮的应用现状和进展,并指出沸石的推广要依赖于沸石改性和与其他工艺的联用技术开发。     

Extra-framework cation release from heulandite-type rich tuffs on exchange with NH(4)(+)

The outgoing cations of Greek heulandite-rich tuff samples (heulandite type-III, 91wt.%, mica 4wt.%, feldspar 5wt. %, CEC 2.22meq/g) were analysed upon exchange with ammonium acetate using atomic absorption spectrometry (AAS). The kinetic curves of each cation were investigated over a total time of contact of 720h with sampling at frequent intervals. The materials were examined by powder X-ray diffraction, SEM-EDS, and AAS. The sorption ability was measured using the ammonium acetate saturation method. It was found that Ca(2+) presents an unexpected extra-framework release and a surprisingly high degree of exchange (90%). The exchange of Mg (57%) is also worthy of note whereas the behavior of K(+) showed an expected rapid initial release. The behavior of Na(+) must be similar. However, its lower concentration in the zeolitic material minimizes its overall significance somewhat. On the other hand, Ca(2+) and Mg(2+) release is kinetically much slower, compared to that of alkali metal ions, and this phenomenon indicates that different exchange energies are needed till final equilibrium.     

Influence of quaternary ammonium on sorption of selected metal cations onto clinoptilolite zeolite

Clay minerals and zeolites have large cation exchange capacities, which enable them to be modified by cationic surfactant to enhance their sorption of organic and anionic contaminants. In this study, the influence of quaternary ammonium surfactants on sorption of five metal cations (Cs+, Sr+, La3+, Pb2+, and Zn2+) onto a clinoptilolite zeolite was investigated. Generally, the metal cation sorption capacity and affinity for the zeolite decreased, indicating that presorbed cationic surfactants blocked sorption sites for metal cations, as the surfactant loading on the zeolite increased. Cesium and Pb2+ sorption was affected to a small extent, indicating that selective sorption for Cs+ and specific sorption for Pb2+ play an important role in addition to cation exchange. Sorption of cationic surfactants on zeolite preloaded with different metal cations showed a strong correlation with the chain length of the surfactant tail group, while the roles of the charges and types of the metal cations were minimal. As the chain length increases, the critical micelle concentration decreases and the surfactant molecules become more hydrophobic, resulting in progressive bilayer coverage. Desorption of presorbed metal cations by cationic surfactants was strongly affected by the surfactant chain length and metal type. More metal cations, particularly Sr2+ and Zn2+, desorbed with an increase in surfactant chain length. The results, in combination with those from organic and oxyanion sorption on surfactant-modified zeolite, may be used for future surfactant modification to target sorption and desorption of a specific type of contaminant or a mixture of different types of contaminants.     

A mechanical pre-treatment process for the valorization of useful fractions from spent batteries

In this paper the authors propose a full-scale plant aimed to pre-treat spent batteries in order to obtain cleaned useful fractions (magnetic and non-magnetic metals, paper, plastic, a fine-sized material made of a metal-carbon mixture). The treating process was designed after having analyzed and tested a representative sample coming from the whole amount of spent batteries collected in 1 month by the public service in and around Turin. The analyses performed on the sample allowed the authors to determine its in-percentage composition in term of type of batteries: 60-70% b.w. (by weight) alkaline, 25-30% b.w. Zn-C and 5-10% b.w. other types. For each type, the composition in term of size (AAA or LR03; AA or LR6; C or LR14; D or LR20; 9 V or 6F22A; 4.5 V or 3R12A) has also been determined.The treatment for the recovery of secondary raw materials foresees the following phases:

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separation of useful types/sizes of exhaust batteries to undergo further treatments by means of a first sieving process;

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liberation of the single components taking advantage of a crushing operation;

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separation of a fine-sized material (to subject to pyro or hydro metallurgic recovery) from a coarse-sized material (to send to secondary smelt foundries and incinerators) by means of a second sieving phase.

On the basis of the results obtained from the crushing/sieving laboratory tests and the chemical characterization, a full-scale plant able to treat about 76,000 t/y of spent batteries has been designed. The cost analysis performed on the proposed treatment plant has given back a unit pre-treatment cost equal to 3€ per ton of processed spent batteries.     

人工沸石对Cr(Ⅲ)的吸脱附的实验研究

采用单变量法研究了人工沸石对Cr3+的最佳吸附粒径、最佳吸附反应条件和吸附动力学。结果表明,在Cr3+初始浓度为20mg/L、沸石投放量为10g/L时,最佳粒径为80目;在Cr3+初始浓度为50mg/L、沸石投放量为10g/L时,最佳振荡时间为70min;Cr3+浓度在20～70mg/L范围内时,人工沸石饱和吸附量随Cr3+的初始浓度增加而增加,二者近似于指数关系;人工沸石吸附Cr3+的过程主要为化学吸附,受表面扩散和颗粒内扩散过程控制。脱附实验表明洗脱性价比最佳的洗脱剂(NaCl)浓度为10g/L,洗脱微振荡-静置沉降最佳时间分布为:微振荡10min,静置沉降50min,洗脱两次后吸附效率下降25%～30%。     

Alkaline hydrothermal conversion of fly ash precipitates into zeolites 3: the removal of mercury and lead ions from wastewater

In this paper, the utilisation of zeolites synthesised from fly ash (FA) and related co-disposal filtrates as low-cost adsorbent material were investigated. When raw FA and co-disposal filtrates were subjected to alkaline hydrothermal zeolite synthesis, the zeolites faujasite, sodalite and zeolite A were formed. The synthesised zeolites were explored to establish its ability to remove lead and mercury ions from aqueous solution in batch experiments, to which various dosages of the synthesised zeolites were added. The test results indicated that when increasing synthesised zeolite dosages of 5-20 g/L were added to the acid mine drainage (AMD) wastewater, the concentrations of lead and mercury in the wastewater were reduced accordingly. The lead concentrations were reduced from 3.23 to 0.38 and 0.17 microg/kg, respectively, at an average pH of 4.5, after the addition of raw FA zeolite and co-disposal filtrate zeolite to the AMD wastewater. On the other hand, the mercury concentration was reduced from 0.47 to 0.17 microg/kg at pH=4.5 when increasing amounts of co-disposal filtrate zeolite were added to the wastewater. The experimental results had shown that the zeolites synthesised from the co-disposal filtrates were effective in reducing the lead and mercury concentrations in the AMD wastewater by 95% and 30%, respectively.     

Optimization of the recovery of plastics for recycling by density media separation cyclones

Material recovery processes are presented as the optimum option for recycling plastic wastes as a means of recovering hydrocarbon resources. There exist a large variety of automated material recovery processes for recycling of such wastes but each with significant limitations. Of these, the separation based on differences in densities is advocated as the optimum process either for producing recycled products or preparing wastes for subsequent recovery processing.Density separation processes based on cyclone type density media separation (DMS) is presented as an important, potential method for increasing plastics recycling process capacities. It is demonstrated to have the capacity to separate a significantly larger range of particle sizes than those presently processed industrially. The mathematical relationship for the prediction of quality of typical LARCODEMS type density media separations by particle size and density as expressed by the Ecart Probable is presented.A proposed device configuration is presented for density media separation to optimize the recovery and purity of both density fractions produced. It is also suggested that to be economically viable, a large scale of operation is required for industrial plastics recycling operations recovering and producing a number of different plastics with a purity to be used as a substitute for virgin material.     

Removal of mercury from aqueous solutions using activated carbon prepared from agricultural by-product/waste

Removal of mercury from aqueous solutions using activated carbon prepared from Ceiba pentandra hulls, Phaseolus aureus hulls and Cicer arietinum waste was investigated. The influence of various parameters such as effect of pH, contact time, initial metal ion concentration and adsorbent dose for the removal of mercury was studied using a batch process. The experiments demonstrated that the adsorption process corresponds to the pseudo-second-order-kinetic models and the equilibrium adsorption data fit the Freundlich isotherm model well. The prepared adsorbents ACCPH, ACPAH and ACCAW had removal capacities of 25.88 mg/g, 23.66 mg/g and 22.88 mg/g, respectively, at an initial Hg(II) concentration of 40 mg/L. The order of Hg(II) removal capacities of these three adsorbents was ACCPH > ACPAH > ACCAW. The adsorption behavior of the activated carbon is explained on the basis of its chemical nature. The feasibility of regeneration of spent activated carbon adsorbents for recovery of Hg(II) and reuse of the adsorbent was determined using HCl solution.     

Controlling substance flows: The case of chlorine

The contribution of chlorinated hydrocarbons (CHCs) to environmental problems in the Netherlands is discussed in an economic context. The economic interactions within the chlorine market, including the link to caustic soda production, are described, and PVC is taken as a case study. Key policy options are evaluated in terms of their potential for environmental improvement. It appears that 95% of CHC emissions causing environmental problems are due to dissipative applications. With respect to the specific problems of ozone depletion and global warming, only a small group of compounds is responsible for most of the impact. Moreover, economic interactions within the group of CHCs can strongly influence the net effect of environmental policy measures. Policies aimed at a reducing volume output of certain specific groups of CHCs will inevitably lead to trade-offs between environmental problems. The environmental impact of a hypothetical ban on CHCs is discussed in relation to the use of PVC as a sink for chlorine. Both these options appear to have drawbacks. Moreover, no absolute conclusion can be drawn until the environmental impact of CHC substitutes is known.     

Improving saline-sodic coalbed natural gas water quality using natural zeolites

Management of saline-sodic water from the coalbed natural gas (CBNG) industry in the Powder River Basin (PRB) of Wyoming and Montana is a major environmental challenge. Clinoptilolie zeolites mined in Nevada, California, and New Mexico were evaluated for their potential to remove sodium (Na+) from CBNG waters. Based on the exchangeable cation composition, naturally occurring calcium (Ca2+)-rich zeolites from New Mexico were selected for further evaluation. Batch adsorption experiments were conducted to evaluate the potential of the Ca(2+)-rich natural clinoptilolites to remove Na+ from saline-sodic CBNG waters. Batch adsorption experiments indicated that Na+ adsorption capacity ofclinoptilolite ranged from 4.3 (4 x 6 mesh) to 7.98 g kg(-1) (14 x 40 mesh). Among the different adsorption isotherms investigated, the Freundlich Model fitted the data best for smaller-sized (6 x 8, 6 x 14, and 14 x 40 mesh) zeolites. Passing the CBNG water through Ca(2+)-rich zeolite columns reduced the salt content (electrical conductivity [EC]) by 72% with a concurrent reduction in sodium adsorption 10 mmol 1/2 L(-1/2). Zeolite technology appears to be an effective water treatment alternative to industrial membrane treatment for removing Na+ from poor-quality CBNG waters.     

Influence of soil geochemical and physical properties on the sorption and bioaccessibility of chromium(III)

There are numerous Cr(III)-contaminated sites on Department of Defense (DoD) and Department of Energy (DOE) lands that are awaiting possible clean up and closure. Ingestion of contaminated soil by children is the risk driver that generally motivates the likelihood of site remediation. The purpose of this study was to develop a simple statistical model based on common soil properties to estimate the hioaccessibility of Cr(III)-contaminated soil upon ingestion. Thirty-five uncontaminated soils from seven major soil orders, whose properties were similar to numerous U.S. DoD contaminated sites, were treated with Cr(III) and aged. Statistical analysis revealed that Cr(III) sorption (e.g., adsorption and surface precipitation) by the soils was strongly correlated with the clay content, total inorganic C, pH, and the cation exchange capacity of the soils. Soils with higher quantities of clay, inorganic C (i.e., carbonates), higher pH, and higher cation exchange capacity generally sequestered more Cr(III). The amount of Cr(III) bioaccessible from the treated soils was determined with a physiologically based extraction test (PBET) that was designed to simulate the digestive process of the stomach. The bioaccessibility of Cr(III) varied widely as a function of soil type with most soils limiting bioaccessibility to <45 and <30% after I and 100 d soil-Cr aging, respectively. Statistical analysis showed the bioaccessibility of Cr(III) on soil was again related to the clay and total inorganic carbon (TIC) content of the soil. Bioaccessibility decreased as the soil TIC content increased and as the clay content decreased. The model yielded an equation based on common soil properties that could be used to predict the Cr(III) bioaccessibility in soils with a reasonable level of confidence.     

Sorption of hazardous metals from single and multi-element solutions by saltbush biomass in batch and continuous mode: interference of calcium and magnesium in batch mode

Batch studies were performed to determine the interference of calcium (Ca) and magnesium (Mg) on the sorption of Cu(II), Cd(II), Cr(III), Cr(VI), Pb(II), and Zn(II) [from CuSO(4), K(2)Cr(2)O(7), Pb(NO(3))(2), Cr(NO(3))(3), ZnCl(2), and Cd(NO(3))(2)] by saltbush (Atriplex canescens) biomass. The results demonstrated that Ca and Mg at concentrations of at least 20 times higher than the concentration of most of the target metals did not interfere with the metal binding. The data show that the batch binding capacity from a multimetal solution at pH 5.0 was (micromol/g) about 260 for Cr(III) and Pb, and about 117, 54, and 49 for Cu, Zn, and Cd, respectively. The use of 0.1M HCl allowed the recovery of 85-100% of the bound Cu, Cr(III), and Pb, and more than 37% of the bound Cd and Zn. The column binding capacity for Pb was about 49 micromol/g from both the single and multimetal solutions, while it was, respectively about 35 and 23 micromol/g for Cr(III). The binding capacity for Cu and Zn from the single and multimetal column experiments was 35 micromol/g and less than 10 micromol/g, respectively. The stripping data from the single column experiment showed that 0.1M HCl allowed the recovery of all the bound Cu and Zn, 90% and 74% of the bound Pb and Cr(VI), respectively, and less than 25% of the bound Cd and Cr(III), while the stripping from the multimetal experiment showed that 0.1M HCl allowed the recovery of all the bound Cu and about 74%, 54%, 43%, and 40% of the bound Pb, Zn, Cd, and Cr(III), respectively.     

Sustainable pattern analysis of a publicly owned Material Recovery Facility in a fast-growing urban setting under uncertainty

Sustainable development goals are achievable through the installation of Material Recovery Facilities (MRFs) in certain solid waste management systems, especially those in rapidly expanding multi-district urban areas. MRFs are a cost-effective alternative when curbside recycling does not demonstrate long-term success. Previous capacity planning uses mixed integer programming optimization for the urban center of the city of San Antonio, Texas to establish that a publicly owned material recovery facility is preferable to a privatized facility. As a companion study, this analysis demonstrates that a MRF alleviates economic, political, and social pressures facing solid waste management under uncertainty. It explores the impact of uncertainty in decision alternatives in an urban environmental system. From this unique angle, waste generation, incidence of recyclables in the waste stream, routing distances, recycling participation, and other planning components are taken as intervals to expand upon previous deterministic integer-programming models. The information incorporated into the optimization objectives includes economic impacts for recycling income and cost components in waste management. The constraint set consists of mass balance, capacity limitation, recycling limitation, scale economy, conditionality, and relevant screening restrictions. Due to the fragmented data set, a grey integer programming modeling approach quantifies the consequences of inexact information as it propagates through the final solutions in the optimization process. The grey algorithm screens optimal shipping patterns and an ideal MRF location and capacity. Two case settings compare MRF selection policies where optimal solutions exemplify the value of grey programming in the context of integrated solid waste management.     

改性沸石对水体中硝酸盐的吸附机理及其残渣的资源化利用

利用HDTMA改性沸石制成吸附剂,研究对水体中硝酸盐的吸附能力和机理及吸附剂残渣的资源化应用前景。结果表明:HDTMA改性沸石可增强其对硝酸盐的吸附能力。通过红外光谱和差热分析它的吸附机理,表明:改性沸石HZ4吸附有十六烷基三甲基溴化铵(HDTMA)分子;吸附剂残渣NHZ4吸附有十六烷基三甲基溴化铵(HDTMA)分子和硝酸盐。盆栽实验结果表明:吸附剂残渣NHZ4能提高玉米生物量,最大增幅为30.4%。     

分子印迹硅纳米改性氧化石墨烯复合材料的制备及其对双酚A的吸附研究

制备了分子印迹硅纳米-氧化石墨烯复合吸附材料,并研究了复合材料对双酚A(Bisphenol A,BPA)的吸附性能.实验结果表明:复合吸附材料对BPA的吸附在35min内达到吸附平衡,Langmuir等温线模型得出最大吸附容量约为338.3mg/g;相对于BPA的结构类似物,对BPA具有良好的选择吸附性能;在溶液pH接...