共查询到20条相似文献,搜索用时 15 毫秒
1.
Nadia Eladlani El Montassir Dahmane Abdelaaziz Ouahrouch Mohammed Rhazi Moha Taourirte 《Journal of Polymers and the Environment》2018,26(1):152-157
Chitosan, its nanoparticles and whiskers present an excellent capacity to complex chromium ions. However, this phenomenon is influenced by different parameters. In our search, we determined the appropriate range of pH to form chitosan–Cr(III), nanoparticles Cr(III) and whiskers–Cr(III) complex. We studied also the influence of chromium concentration and nature of chitosan-based materials on complexation process. Our main aim is approximate the optimal conditions to remove chromium(III) from tanning bath, recuperated from tannery wastewater of Marrakech in Morocco. However, the results of adsorption kinetic in tannery wastewater revealed that chitosan, its nanoparticles, whiskers and biocomposites are good sorbent of chromium as well, even if the adsorbed quantity is less compared to chromium solution. Although, according to ICP-OES analysis in this real effluent, nanoparticles are the best complexing ligand, after 24 h of contact nanoparticles can remove 70% of chromium from this tannery wastewater. 相似文献
2.
研究了在散射光下铁(III)-丙酮酸盐配合物对铬(V I)的光还原反应;考察了溶液pH、铁(III)、丙酮酸钠、铬(V I)浓度对反应的影响;分析了铬(V I)光还原反应的动力学。实验结果表明:铁(III)-丙酮酸盐配合物体系能在较弱的散射光下还原铬(V I)。在铬(V I)浓度为19.2μm o l/L、铁(III)浓度为10.0μm o l/L、丙酮酸钠浓度为240μm o l/L、pH为3.0、光照240m in的条件下,铬(V I)的还原率达到99.7%。从表观动力学方程的反应级数看,铁(III)的级数(0.83)最高,铁(III)浓度是影响铬(V I)光还原反应速率的主要因素,铁(II)是铬(V I)光还原的主要还原剂。 相似文献
3.
用钡渣处理含铬(Ⅵ)废水 总被引:3,自引:0,他引:3
探索了用钡渣处理含铬(Ⅵ)废水的最佳实验条件,在废水pH小于6、钡渣与铬(Ⅵ)质量比为60~80、钡渣粒度为180~200目、反应时间为90min的条件下,废水中铬(Ⅵ)的去除率较高,钡渣对含铬(Ⅵ)废水的去除行为符合Langmuir等温方程。钡渣处理含铬(Ⅵ)废水的工业化应用试验表明,其工艺简单,操作方便,成本低。 相似文献
4.
含铬电镀废水中Cr(Ⅵ)的萃取分离研究 总被引:12,自引:1,他引:11
用体积分数为40%的磷酸三丁酯-煤油溶液为萃取剂,采用溶液萃取法处理含铬[Cr(Ⅵ)]电镀废水。预先调节废水中Cr(Ⅵ)的质量浓度约为100mg/L,溶液酸度为1.3-1.5mol/L,相比为1∶2,振荡时间为35min,于室温下进行二级萃取处理,Cr(Ⅵ)的萃取率可达到99%以上。萃余液中Cr(Ⅵ)的残余质量浓度降至0.5mg/L以下,达到国家排放标准。对负载有机相用质量分数为10%的Na2SO3溶液进行反萃,即可得到再生,循环使用。 相似文献
5.
Chen Changcheng Luo Mina Chen Fu Huang Chao Zhu Chunmei Wu Hongjun 《Journal of Polymers and the Environment》2022,30(6):2547-2558
Journal of Polymers and the Environment - Herein, we report the preparation of Fe(III) complexed polydopamine modified Mg/Al layered double hydroxides composite material (LDHs@PDA-Fe(III)) and its... 相似文献
6.
Sawada A Mori K Tanaka S Fukushima M Tatsumi K 《Waste management (New York, N.Y.)》2004,24(5):483-490
A new process for the removal of hexavalent chromium [Cr(VI)] contaminated soil is described. The process provides for an efficient removal of anionic chemicals from contaminated soils. Chromate anions were removed from the soil to the anodic reservoir by the moving force of electromigration. In this process, the chromate anions that accumulate in the anodic reservoir are simultaneously eliminated by using a column packed adsorbent. The adsorbent (immobilized tannin) used was chemically incorporated into cellulose. Cr(VI) was found to be adsorbed to this adsorbent efficiently. In the electrokinetic process, the pH of the aqueous solution in the anodic reservoir was decreased by the electrolysis of water. In the present study, the pH of the solution in the anodic reservoir is maintained at pH 6 by the addition of an aqueous alkaline solution during the electrokinetic process. The advantage of pH control is that it promotes the release of Cr(VI) from the soil by electromigration, thus permitting the maximum adsorption of Cr(VI) on the immobilized tannin. Simultaneous collection of Cr(VI) from the anodic reservoir leads to the protection from secondary contamination with Cr(VI). 相似文献
7.
Jiayou Ji Huizhi Xiong Zhenni Zhu Liang Li Yineng Huang Xianghua Yu 《Journal of Polymers and the Environment》2018,26(5):1979-1985
Three-dimensional polypyrrole/chitosan nanocomposite monoliths are fabricated by polymerization of pyrrole in chitosan aqueous solution. The static polymerization of pyrrole monomer and the cross-linking of chitosan by glutaraldehyde occur simultaneously, resulting in the self-assembly of polypyrrole/chitosan nanocomposite aerogel monolith. The addition of methyl orange and glutaraldehyde and the static reaction play key roles in the formation of the self-standing aerogel monolith. The as-prepared monolith with larger specific surface area exhibits much better adsorption capability for Cr(VI) removal in comparison with that prepared without the addition of glutaraldehyde. The adsorption process and adsorption isotherms are found to well follow the pseudo-second-order and Langmuir models, respectively. Furthermore, this polypyrrole/chitosan nanocomposite monolith is stable and recyclable. About 73.5% of the initial adsorption capability is kept after eight adsorption–desorption cycles. The polypyrrole/chitosan nanocomposite monolith can be a promising candidate for the efficient removal of Cr(VI). 相似文献
8.
This paper deals with a new application of poly 3-methyl thiophene synthesized chemically onto sawdust (termed as P3MTh/SD)
as an effective adsorbent for removal of Cr(VI) ions from aqueous solutions using column system. Chemical synthesis of poly
3-methyl thiophene was performed by addition of ferric chloride (in chloroform) as oxidant to sawdust which had previously
been soaked in monomer solution. All the sorption experiments were conducted using dynamic or column system at room temperature.
The effect of important parameters such as pH and initial concentration on uptake of Cr(VI) was investigated. In order to
find out the possibility of the regeneration and reuse of the exhausted adsorbent, desorption studies were also performed.
The currently introduced adsorbent was found to be an efficient adsorbent for removal of highly toxic and hazardous Cr(VI)
ions from aqueous solutions. As our breakthrough analysis has indicated, each gram of P3MTh/SD is able to remove more than
95% of Cr(VI)ions from 300 mL of Cr(VI) polluted solution with the initial concentration of 25 mg L−1 in column system. Sorption/desorption of Cr(VI) ions was found to be a highly pH dependent processes. 相似文献
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Charlotta Carlsson Sanders 《Waste management (New York, N.Y.)》1996,16(8):683-689
One of ABB Atom's methods, ELDECON, is an electrochemical process for decontamination of components used in nuclear power plants. ELDECON removes radioactive species while producing small amounts of waste. However, the waste sludge that is produced in the ELDECON process contains chrornate (Cr(VI)). According to the US Cod of Feguration, 40 CFR 261, if a process in any step creates chromate, the final waste has to be tested in a toxicity characteristic leachate procedure. In order to pass the test, the chromate has to be reduced to chromium (Cr(III)). Electrochemistry has proven to be a valuable tool. When incorporating indirect electrolysis into the ELDECON concept, the chromate ions are reduced. This is done by the use of an electrochemical cell (reactor bed). The method involves ferric nitrate as a reagent which, besides converting the chromate completely, also decreases the reaction time. The reaction time and the amount of solution treated in the cell have a close to linear relationship (i.e. the reaction time is proportional to the amount of solution). This makes the test cell feasible to scale up and use in the industry. 相似文献
12.
Adrian Frank Herbort Michael Toni Sturm Simone Fiedler Golnar Abkai Katrin Schuhen 《Journal of Polymers and the Environment》2018,26(11):4258-4270
The substance class of inert organic-chemical stressors (IOCS) describes organic-chemical (macro-) molecules, which demonstrate a high level of persistence upon entry in the ecosystem, and whose degradation is limited. These synthetically produced organic-chemical macromolecules, which are often derived from the polymerization of different monomers, are, in the form of plastics, indispensable in the everyday world. They enter the environmental compartments and cause great damage due to primary (industry, cosmetic, washing of textile), and secondary (degradation) entry. If these particles get into aquatic systems, this has fatal consequences for the ecosystem such as the death of marine animals, or bioaccumulation. Wastewater treatment plants are reaching their limits and require innovative ideas for the sustainable removal of microplastic. This article examines a new approach to the removal of polymers from aquatic systems (lab scale) by using sol–gel induced agglomeration reactions to form larger particle agglomerates. These enlarged agglomerates can be separated much more easily from the wastewater, since they float on the water surface. Separation systems, e.g. sand trap can easily be used. A further advantage is that the agglomeration can be carried out completely independently of the type, size, and amount of the trace substance concentration as well as of the external influences (pH value, temperature, pressure). Thus, this new type of particle separation can not only be used in sewage treatment plants, but can also be transferred to decentralized systems (e.g. implementation in industrial processes). 相似文献
Graphical Abstract
13.
淀粉基黄原酸盐合成新工艺及其在废水处理中的应用 总被引:11,自引:0,他引:11
研究了淀粉基黄原酸盐的合成新工艺,通过正交试验选定了最佳工艺条件。用该产品进行了电镀废水处理试验,去除重金属效果良好。 相似文献
14.
Forouzesh Rad Bahar Mahdavi Hossein Forouzesh Rad Mahsa Baghdadi Majid 《Journal of Polymers and the Environment》2022,30(9):3875-3889
Journal of Polymers and the Environment - In this study, an NH2-MIL-53(Fe) functionalized membrane was fabricated for Cr(VI) removal from contaminated groundwater. Design-Expert was employed to... 相似文献
15.
以铬渣和粉煤灰为混合填充体系的主要填料,采用柱子淋洗法,通过改变混合填料的配比来研究其对铬渣中Cr(Ⅵ)的阻留作用。试验结果表明,各种混合填充体系对Cr(Ⅵ)均有一定程度的阻留作用,其中I—5校对Cr(Ⅵ)的阻留固定效果最佳,淋出液中Cr(Ⅵ)的质量分数为0.删%,相对阻留效果达94.53%。 相似文献
16.
硫酸生产废水中砷去除方法的研究 总被引:4,自引:0,他引:4
对硫酸生产中水洗净化工序排放的废水分别采用灰灰石和鼓风氧化法,铁屑法和铁盐法进行处理试验,结果表明,采用铁盐法级处理工艺处理废废水是可行的,控制组处理的PH分别为8-10和8-9,Fe/As摩尔比分别为1和5,当进水As含量为115mg/L时,经两组处理后,出水As含量〈0.5mg/L,重金属离子,PH,SS等指标均符合国家排放标准。 相似文献
17.
Natural Fiber Reinforced Poly(vinyl chloride) Composites: Effect of Fiber Type and Impact Modifier 总被引:1,自引:0,他引:1
Poly(vinyl chloride) (PVC) and natural fiber composites were prepared by melt compounding and compression molding. The influence
of fiber type (i.e., bagasse, rice straw, rice husk, and pine fiber) and loading level of styrene-ethylene-butylene-styrene
(SEBS) block copolymer on composite properties was investigated. Mechanical analysis showed that storage modulus and tensile
strength increased with fiber loading at the 30% level for all composites, but there was little difference in both properties
among the composites from various fiber types. The use of SEBS decreased storage moduli, but enhanced tensile strength of
the composites. The addition of fiber impaired impact strength of the composites, and the use of SEBS led to little change
of the property for most of the composites. The addition of fiber to PVC matrix increased glass transition temperature (Tg), but lowered degradation temperature (Td) and thermal activation energy (Ea). After being immersed in water for four weeks, PVC/rice husk composites presented relatively smaller water absorption (WA)
and thickness swelling (TS) rate compared with other composites. The results of the study demonstrate that PVC composites
filled with agricultural fibers had properties comparable with those of PVC/wood composite. 相似文献
18.
Daniele Battegazzore Jenny Alongi Alberto Frache 《Journal of Polymers and the Environment》2014,22(1):88-98
Natural filler/poly(lactic acid)-Based composites have been prepared by melt blending in order to investigate the resulting thermal, mechanical, and oxygen permeability properties. To this aim, several wastes or by-products (namely, cellulose fibers, wood sawdust, hazelnut shells, flax fibers, corn cob and starch) have been used, ranging from 10 to 30 wt%. The presence of these fillers is responsible of a slight reduction of the polymer degradation temperature in nitrogen as well as of a significant increase of the storage modulus as a function of the filler content. The experimental data obtained by dynamic mechanical analysis have been mathematically fitted, employing three micromechanical models (namely, Voigt, Reuss and Halpin–Tsai). Furthermore, the presence of cellulose or starch has turned out to significantly reduce the polymer oxygen permeability. Finally, in order to fully assess the feasibility of such materials, an economic analysis has been carried out and discussed. 相似文献
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Q. F. Shi H. Y. Mou L. Gao J. Yang W. H. Guo 《Journal of Polymers and the Environment》2010,18(4):567-575
The melting and crystallization behavior of pure poly (lactic acid) (PLA) and PLA composites (1% Bamboo Fiber (BF)/PLA, 1%
Talc/PLA, 1% BF/1% Talc/PLA) were studied with differential scanning calorimetry (DSC). DSC curves for PLA composites were
obtained at various cooling rates, the crystallization temperature and heat of crystallization of PLA composites decreased
almost linearly with increasing of log (cooling rate). Moreover, BF has minor effect and talc has the great effect on the
crystallization temperature in the PLA composites. With increasing of cooling rate, the main melting temperature of PLA composites
decreased. In pure PLA and 1% BF/PLA, the double-melting behavior appeared in the heating curves after slow rate of cooling,
and there was the opposite phenomenon of double-melting behavior in other two PLA composites. BF promotes forming the imperfect
crystal in the PLA composites during heating process. With increasing of heating rate, the main melting temperature of PLA
composites increased except the 1% BF/PLA. At various heating rates, the defects of BF structure promoted the melt-recrystallization
and talc promoted forming the small crystals. At last, the recrystallization model was given. 相似文献