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The prediction of adsorption isotherms of ester vapors on hypercrosslinked polymeric adsorbent

Liuyan WU,Lijuan JIA,Xiaohan LIU,Chao LONG

《环境科学与工程前沿（英文）》 2016年第10卷第3期页码 482-490 doi: 10.1007/s11783-015-0826-6

摘要： Adsorption isotherms of methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate and ethyl propionate on hypercrosslinked polymeric resin (ND-100) were measured at 303K, 318K and 333K,respectively, and well fitted by Dubinin–Astakhov (DA) equation. The plots of the adsorbed volume ( ) versus the adsorption potential ( ) at three different temperatures all fell basically onto one single curve for every ester. A predicted model based on DA equation was obtained on the basis of adsorption equilibrium data of methyl acetate, ethyl acetate and ethyl propionate at 318K. The model equation successfully predicted the adsorption isotherms of methyl acetate, ethyl acetate and ethyl propionate on ND-100 at 303K, and 333K, and also gave accurate predictive results for adsorption isotherms of the other two ester compounds (propyl acetate and isopropyl acetate) on ND-100 at 303K, 318K and 333K. The results proved the effectiveness of DA model for predicting the adsorption isotherms of ester compounds onto ND-100. In addition, the relationship between physico-chemical properties of adsorbates and their adsorption properties was also investigated. The results showed that molecular weight, molar volume and molar polarizability had good linear correlations with the parameter (which represents adsorption characteristic energy) of DA equation.

关键词： hypercrosslinked polymeric adsorbent adsorption isotherm ester prediction

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Removal of Zn

Feng XUE, Beicheng XIA, Rongrong YING, Shili SHEN, Peng ZHAO

《环境科学与工程前沿（英文）》 2013年第7卷第4期页码 531-538 doi: 10.1007/s11783-013-0506-3

摘要： Biosorption of Zn from aqueous solutions by biomass of was investigated. The removal rates of Zn by under different parameters (e.g., solution pH, bio-sorbent dosage and initial Zn concentration) were studied. The inhibition of ’s biosorption by anionic ligands EDTA (Ethylene Diamine Tetraacetic Acid), acetate and citrate) implied that EDTA and citrate might be used as eluting reagents. Regular and simultaneous solution pH change and light metal ions release after biosorption indicated that an ion exchange mechanism was involved. From FT-IR (Fourier Transform Infrared) spectroscopy, the main functional groups participated in biosorption were found. Biosorption of Zn by could be well described by the Freundlich and Langmuir models. In conclusion, the biomass of showed high potential for the treatment of wastewater containing Zn .

关键词： biosorption Agaricus bisporus zinc ion exchange FT-IR isotherms

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Removal of phenol by powdered activated carbon adsorption

Yan MA, Naiyun GAO, Wenhai CHU, Cong LI

《环境科学与工程前沿（英文）》 2013年第7卷第2期页码 158-165 doi: 10.1007/s11783-012-0479-7

摘要： In this study, the adsorption performance of powdered activated carbon (PAC) on phenol was investigated in aqueous solutions. Batch adsorption studies were performed to evaluate the effects of various experimental parameters like PAC type, PAC dose, initial solution pH, temperature and pre-oxidation on the adsorption of phenol by PAC and establish the adsorption kinetics, thermodynamics and isothermal models. The results indicated that PAC adsorption is an effective method to remove phenol from water, and the effects of all the five factors on adsorption of phenol were significant. The adsorption rate of phenol by PAC was rapid, and more than 80% phenol could be absorbed by PAC within the initial 10 min. The adsorption process can be well described by pseudo-second-order adsorption kinetic model with rate constant amounted to 0.0313, 0.0305 and 0.0241 mg·μg ·min with coal, coconut shell and bamboo charcoal. The equilibrium data of phenol absorbed onto PAC were analyzed by Langmuir, Freundlich and Tempkin adsorption isotherms and Freundlich adsorption isotherm model gave the best correlation with the experimental data. Thermodynamic parameters such as the standard Gibbs free energy (? ), enthalpy (? ) and entropy (? ) obtained in this study indicated that the adsorption of phenol by PAC is spontaneous, exothermic and entropy decreasing.

关键词： phenol powdered activated carbon adsorption kinetics isotherms

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Chloride binding and time-dependent surface chloride content models for fly ash concrete

S. MUTHULINGAM,B. N. RAO

《结构与土木工程前沿（英文）》 2016年第10卷第1期页码 112-120 doi: 10.1007/s11709-015-0322-x

摘要： Corrosion of embedded rebars is a classical deterioration mechanism of reinforced concrete structures exposed to chloride environments. Such environments can be attributed to the presence of seawater, deicing or sea-salts, which have high concentrations of chloride ion. Chloride ingress into concrete, essential for inducing rebar corrosion, is a complex interaction between many physical and chemical processes. The current study proposes two chloride ingress parameter models for fly ash concrete, namely: 1) surface chloride content under tidal exposure condition; and 2) chloride binding. First, inconsistencies in surface chloride content and chloride binding models reported in literature, due to them not being in line with past research studies, are pointed out. Secondly, to avoid such inconsistencies, surface chloride content and chloride binding models for fly ash concrete are proposed based upon the experimental work done by other researchers. It is observed that, proposed models are simple, consistent and in line with past research studies reported in literature.

关键词： binding isotherms chloride ingress concrete fly ash surface chloride content

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Removal of Rhodamine B from aqueous solutions and wastewater by walnut shells: kinetics, equilibrium and thermodynamics studies

Jasmin Shah, M. Rasul Jan, Attaul Haq, Younas Khan

《化学科学与工程前沿（英文）》 2013年第7卷第4期页码 428-436 doi: 10.1007/s11705-013-1358-x

摘要： An adsorption study of Rhodamine B (RB) dye from aqueous solutions was carried out using walnut shells pretreated by different methods. In addition to the effects of the pretreatment, the effects of various parameters like pH, adsorbent dose, contact time, initial dye concentration and temperature on the adsorption of RB was studied. The adsorption process was highly pH dependent and a maximum adsorption was achieved at pH 3.0. The best fit for the rates of dye adsorption was a pseudo-second-order kinetic model with good correlation coefficients ( >0.99). Langmuir isotherms were used to determine that the maximum loading capacity of the different walnut shells and the RB capacities ranged from 1.451–2.292 mg·g . The dye adsorption was also evaluated thermodynamically. Positive standard enthalpy (? °) values were obtained indicating that the RB adsorption process is endothermic as well as ? ° and ? ° values showed that adsorption process is spontaneous with an increased randomness at the solid-liquid interface. Desorption studies were carried out to explore the feasibility of regenerating the used walnut shells and it was found that 97.71%–99.17% of the retained RB was recovered with 0.1 mol?L NaOH solution. The walnut shells were also successfully used to remove RB from industrial effluents.

关键词： Rhodamine B walnut shell adsorption kinetics isotherms regeneration