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Advances in Environmental Technology - Volume:4 Issue: 2, Spring 2018

Advances in Environmental Technology
Volume:4 Issue: 2, Spring 2018

  • تاریخ انتشار: 1397/09/14
  • تعداد عناوین: 6
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  • Mehrnaz Asefi, Rasool Zamani, Ahmadmahmoodi* Pages 75-81
    Rapid population growth as well as agricultural and industrial development have increased the contamination of Iranian rivers. This study utilized principal components analysis (PCA) to determine the degree of significance of qualitative parameters of water resources in the Karkheh River in southwestern Iran. Cluster analysis (CA) grouped the monitoring stations based on the water quality data under measurement. The first three components obtained from the PCA accounted for 39.68, 35.04, and 17.76% of the total variance, respectively; these three components explained a total of 92.49% of the variance of the data sets. The PCA factors indicated that the parameters influencing changes in water quality were generally related to weathering and land washing in response to floods, organic contamination from household wastewater, waste from sand washing, and runoff from chemical fertilizers. Moreover, the PCA results indicated that the relative quality of the river water in the downstream areas, when compared with upstream areas, was worse due to the greater concentration of contamination sources in the vicinity of the monitoring stations. Given Iran’s water crisis, the preservation and reclamation of this valuable resource require greater attention from the relevant authorities
    Keywords: Cluster analysis, Principal components analysis, Water Quality, Karkheh River
  • Seyedeh Zahra Mousavi, Mehrdad Manteghian *, Seyed Abbas Shojaosadati, Hassan Pahlavanzadeh Pages 83-93
    A straightforward procedure to synthesize keratin nanoparticles (KNP) from chicken feathers was introduced. The characterization of the synthesized nanoparticles was done using Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM). The FTIR analysis revealed no significant chemical change after the nanoparticle synthesis. TEM imaging indicated the synthesis of KNPs with a spherical morphology and mean size of 42 nm. The DLS results indicated that the synthesized KNPs were stable in aqueous media by having a zetapotential of lower than -30 mV. The produced KNPs were then evaluated for the biosorption of Cu (II) from aqueous solutions. The analyzed adsorption isotherm data revealed the change from a Redlich-Peterson isotherm to a Langmuir one by increasing the biosorbent dosage, which could be attributed to the more prepared adsorption sites. The experiments of the effect of the biosorbent dosage suggested the best removal at a KNP dose of 3.0 g/L. At this dosage, the maximum Cu (II) adsorption capacity and Langmuir constant were 50 mg/g and 10.8×10-3 L/mg, respectively; the adsorption kinetic followed the pseudo-second order model.
    Keywords: chicken feather, keratin nanoparticle, biosorbent, adsorption isotherm, Cu(II) removal
  • Sepideh Masoumi Khosroshahi, Alireza Miroliaei *, Younes Jafarzadeh Pages 95-105
    Polyvinyl chloride (PVC) membranes containing pristine and modified multiwall carbon nanotube (MWCNT) were prepared and characterized. MWCNT was modified in order to achieve well-dispersion within the membranes. The results of FTIR analysis revealed that MWCNT was successfully carboxylated. The FESEM images indicated that the number of pores on the surface of membranes increased at the presence of pristine and modified MWCNT and the pore size distribution curves shifted towards smaller pores. The hydrophilicity, pure water flux, tensile strength and abrasion resistance of the membranes increased with increasing the content of MWCNT and COOH-MWCNT up to 0.3 wt. % and then decreased due to the agglomeration of nanotubes. Nevertheless, at the same content of nanotubes, COOH-MWCNT had more effect than MWCNT. The performance of the membranes was studied by filtration of humic acid (HA) solution and the results showed that HA rejection reached a peak of 96.88% for 0.3 wt. % PVC/MWCNT-COOH nanocomposite membrane. Finally, it was found that the antifouling properties of the membranes increased with increasing nanotube content, especially COOH-MWCNT.
    Keywords: PVC, MWCNT, Membrane, Ultrafiltration, Humic acid
  • hakimeh sharififard, asghar lashanizadegan *, rahman pazira, parviz darvishi Pages 107-117
    Xylene is an aromatic hydrocarbon that is a highly toxic compound. Therefore, it is essential to remove this component from wastewater before discharging it to the environment. In this research work, palm kernel biomass was activated chemically by H3PO4 and synthesized activated charcoal was applied to separate xylene from aqueous media. The prepared activated charcoal was characterized using FTIR, BET, SEM, pHzpc measurement, Boehm analysis methods. The characterization tests indicated that the produced activated carbon has acidic character with various functional groups and micropores structure. The values of external mass transfer coefficients ranged from 1.87×10-5 to 1.90×10-5. By increasing the temperature, the pore and surface diffusion coefficients were increased from 1.15×10-9 to 1.91×10-9 and 6.98×10-16 to 7.58×10-16, respectively. Sensitivity analysis indicated which the pore diffusion and film diffusion are the main mass transfer parameters. Equilibrium analysis also revealed that the multilayer model with saturation could well describe the data. The number of adsorbate ions for one site, the number of adsorption layers, density of receptor site, and the energy of adsorption at layers were determined using statistical physics modelling. The maximum capacity of prepared activated charcoal at the experimental condition for xylene adsorption was 23.48 mg g-1.
    Keywords: Activated charcoal, Palm kernel waste, Xylene, Adsorption
  • kianoosh shojae, Majid Mahdavian* Pages 119-129
    Hydrogen fuel is the cleanest fuel available. This fuel can be used as an additive in the diesel engine. Diesel engines have the advantages of strong power, high thermal efficiency and low fuel costs. There have been extensive studies on the use of hydrogen fuel in diesel engines in recent years. However, the simultaneous effect of using gaseous hydrogen fuel and changing injection strategy needs further investigation specially for the Cummins ISM370 engine. This work considers almost all functional and emission parameters, simultaneously. This procedure can be effective to achieve balanced conditions when 6% H2 (by volume) is injected into the Cummins ISM 370 diesel engine (under different engines). In addition, due to changing fuel compound used in engine, injection timing and temperature of engine should be redesigned to better operating. For simulation of engine, a CFD code was used. In order to validity and verify the simulation predicted mean pressure and the rate of heat release are compered to experimental data and results gave appropriate accordance. Results show that most of exhaust emissions such as NO, CO, etc. are dramatically reduced by using gaseous hydrogen under various engine speeds. It is determined that with addition of 6% H2 within the engine, indicated thermal efficiency is increased by around 39%; and NO, soot, CO and CO2 emissions are reduced by 5%, 75%, 70%, and 30%, respectively, under 1600 rpm speed. It is also found that the best injection timing that makes a balance between exhaust emissions and performance parameters is 4 deg BTDC under 2000 rpm. Moreover, the best injection temperature is 330 K among of three considered injection temperatures.3
    Keywords: Hydrogen addition, ISM 370 diesel engine, engine speed, Injection timing, Performance
  • Farshid Taran *, Ali, Ashraf Sadraddini, Amir, Hossein Nazemi Pages 131-138
    Laboratory and field experiments have shown that dispersivity is one of the key parameters in contaminant transport in porous media and varies with elapsed time. This time-dependence can be shown using a time-variable dispersivity function. The advantage of this function as opposed to constant dispersivity is that it has at least two coefficients that increase the accuracy of the dispersivity prediction. In this study, longitudinal dispersivity values were obtained for the conservative NaCl solute transport in a laboratory porous medium saturated with tap water. The results showed that the longitudinal dispersivity initially increased with time (pre-asymptotic stage) and eventually reached a constant value (asymptotic stage). Four functions were used to investigate the time variations of dispersivity: linear, power, exponential and logarithmic. In general, because of the linear increase of dispersivity during a long time of transport, the linear function with R2=0.97 showed better time variations than the other three functions; the logarithmic function, having an asymptotic nature, predicted the asymptotic stage successfully (R2=0.95). The ratio of the longitudinal dispersivity to the medium length was not constant during the transport process and varied from 0.01 to 0.05 cm with elapsed time.
    Keywords: contaminant transport, Porous medium, Longitudinal dispersivity, Time-variable functions