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Comparison of ARIMA and NNAR Models for Forecasting Water Treatment Plant's Influent Characteristics
Afshin Maleki,Simin Nasseri,Mehri Solaimany Aminabad,Mahdi Hadi 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.9
A reliable forecasting model for each Water Treatment Plant (WTP) influent characteristics is useful for controlling the plant's operation. In this paper Auto-Regressive Integrated Moving Average (ARIMA) and Neural Network Auto-Regressive (NNAR) modeling techniques were applied on a WTP's influent water characteristics time series to make some models for short-term period (to seven days ahead) forecasting. The ARIMA and NNAR models both provided acceptable generalization capability with R2s ranged from 0.44 to 0.91 and 0.45 to 0.92, respectively, for chloride and temperature. Although a more prediction performance was observed for NNAR in comparison with ARIMA for all studied series, the forecasting performance of models was further examined using Time Series Cross-Validation (TSCV) and Diebold-Mariano test. The results showed ARIMA is more accurate than NNAR for forecasting the horizon-daily values for CO2, Cl and Ca time-series. Therefore, despite of the good predictive performance of NNAR, ARIMA may still stands as better alternative for forecasting task of aforementioned series. Thus, as a general rule, not only the predictive performance using R2 statistic but also the forecasting performance of a model using TSCV, are need to be examined and compared for selecting an appropriate forecasting model for WTP's influent characteristics.
Adsorption of hexavalent chromium by metal organic frameworks from aqueous solution
Afshin Maleki,주상우,Bagher Hayati,Maryam Naghizadeh 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.28 No.-
A metal–organic frameworks (MOFs) based on copper-benzenetricarboxylates is applied to theadsorption of hexavalent chromium from aqueous solution. Characterization of Cu-BTC was achieved byXRD, SEM micrographs, nitrogen adsorption–desorption analysis and FT-IR spectra. The kineticcharacteristics and thermodynamic parameters are also analyzed. The experimental isotherm data areanalyzed using Langmuir and Freundlich isotherm equations. Thermodynamic parameters arecalculated by the Gibbs free energy function, confirming that the adsorption process was spontaneousand accompanied by exothermic. The maximum removal has been achieved at pH = 7.0. Possiblemechanism and adsorption behavior of hexavalent chromium onto Cu-BTC are investigated.
Afshin Maleki,Amir Hossein Mahvi,Roya Ebrahimi,Yahya Zandsalimi 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.6
The degradation of two commercially available dyestuffs (C.I. Reactive Black 5 and C.I. Disperse Orange 25) by ultraviolet radiation (UV), ultrasonic irradiation (US), UV/H2O2 and US/H2O2 processes was investigated in a laboratory-scale batch photoreactor equipped with a 55 W immersed-type low-pressure mercury vapor lamp and a sonoreactor with low frequency (42 kHz) plate type transducer at 170W of acoustic power. The toxicity was also evaluated in acute toxicity studies using Daphnia magna. Results showed that color removal efficiencies by US and US/H2O2processes were negligible for both dyes. Almost complete disappearance of Reactive Black 5 (97.9%) in UV/H2O2 process was possible after 5 min of irradiation. The maximum color removal efficiency of Disperse Orange 25 after 10min of irradiation, however, was only 9.2% and reached a maximum value of 41% after 120 min of irradiation. Pseudofirst order kinetics with respect to dyestuffs concentrations was found to fit all the experimental data. The results clearly showed that both dyes examined were toxic to D. magna and resulted in quite low LC50 values.
Khosro Hossienzadeh,Afshin Maleki,Hiua Daraei,Mahdi Safari,Radheshyam Pawar,이승목 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.8
The present study investigated the efficiency of transition metal-doped ZnO nanoparticles (NPs) in the removal of Direct Blue 71 from aqueous solutions through photocatalytic (UV and visible light) and sonocatalytic processes. The ZnO particles were synthesized and analyzed by the SEM, XRD, FTIR, AFM, DLS, and zeta potential. The reaction conditions were optimized by concerned catalyst (i.e., dopant percentage and catalyst amount), solution pH, catalyst dose and initial dye concentration. The results demonstrated that the Ag-doped ZnO NPs could provide the highest UV light-based photocatalytic efficiency, while the Cu-doped NPs present the greatest sonocatalytic and visible light-based photocatalytic efficiencies. In all processes, the dye removal efficiency was better in acidic pH. Based on the insignificant difference of efficiency over the acidic range of pH, the natural pH of the dye, i.e., 5.6, was considered as the optimal pH value. Also, the increase of dopant percentage enhanced the decolorization efficiency of the catalysts. However, 2.5% dopant amount was selected as the optimal dopant content due to the negligible difference in the decolorization percentages observed using the 2.5 and 5% dopant percentages. Furthermore, the increase of catalyst dose and contact time increased the removal efficiency, while the increase of initial dye concentration resulted in a lower extent of dye decolorization.
Roya Ebrahimi,Afshin Maleki,Yahya Zandsalimi,Reza Ghanbari,Behzad Shahmoradi,Reza Rezaee,Mahdi Safari,주상우,Hiua Daraei,Shivaraju Harikaranahalli Puttaiah,Omid Giahi 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.73 No.-
The present study aimed at evaluating the application of tungsten oxide-doped zinc oxide nanoparticlesfor the photocatalytic degradation of Direct Blue 15 dye in a sequencing batch reactor. ZnO nanoparticleswere doped with WO3 through hydrothermal synthesis method. To characterize the synthesizednanoparticles scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy,atomic force microscopy, zeta potential analysis, and ultraviolet–visible spectroscopy were used. Theradiation source in this study wasfive 6 W UV lamps. Operational parameters affecting the process,namely pH, light intensity, dopant percentage, dye concentration, and contact time, were evaluated. Theresults of the present study revealed that the efficiency of the photocatalytic process for the degradationof organic dyes was higher at acidic pH values than neutral or basic values. In addition, upon increasingthe light intensity from 172 to 505 W/m2, the efficacy of dye degradation was enhanced from 27.8 to73.5%. Increasing the concentration of the dopant percentage from 1 to 5% w/v increased the degradationefficacy from 30.69 to 73.1%. Increasing the initial dye concentration from 20 to 100 mg/L decreased thedegradation efficacy from 86.9 to 37.5%. Photocatalytic process using WO3-doped ZnO nanoparticlesfixedon a glass surface thus was proven to show a good efficiency for the degradation of organic dye in aquaticsolutions.
Synthesis of cationic polymeric adsorbent and dye removal isotherm, kinetic and thermodynamic
Niyaz Mohammad Mahmoodi,Unes Sadeghi,Afshin Maleki,Bagher Hayati,Farhood Najafi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5
Poly(quaternary ammonium salt) (PQAS) as a cationic polymeric adsorbent was synthesized and characterized by FTIR. Isotherm, kinetic and thermodynamic of dye removal from single and binary systems was investigated. Acid Blue 25 (AB25) and Acid Red 18 (AR18) were used. The effect of operational parameters (adsorbent dose, pH, dye concentration and salt) on dye removal was studied. The dye removal followed the Langmuir isotherm and pseudo-first order kinetics. The adsorbent maximum dye adsorption capacity (Q0) was 2000 and 1667 mg/g for AB25 and AR18, respectively. The thermodynamic data showed that dye adsorption was spontaneous, endothermic, and a physisorption reaction.