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Farnaz Tahmasebi,Mahmood Alimohammadi,Ramin Nabizadeh,Mehdi Khoobi,Kamaledin Karimian,Ahmad Zarei 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.6
We investigated the removal efficiency of humic acid from aqueous solutions by cotton coated with graphene oxide. This research has been conducted as batch on an experimental scale. A self-arrangement approach was introduced in fabrication of the cotton adsorbent coated with graphene oxide. To determine the effect of parameters, including initial concentration, pH, adsorbent dosage and contact time, central composite design (CCD) was employed in response surface method (RSM). The adsorption kinetics were determined based on different times of adsorption of humic acid. Further, the adsorption isotherms were also examined using different concentrations of humic acid. The results obtained showed that with increasing adsorbent dosage and contact time, the removal efficiency increased, while with increasing pH and initial concentration of humic acid, the removal efficiency decreased. The optimal values based on RSM method were obtained as the following: humic acid initial concentration=13.61mg/L, pH=3.87, adsorbent dosage=0.61 g, and contact time=168.43min. Langmuir isotherm with R2=0.9987 has been the most suitable model for explaining the adsorption process. Investigation of the adsorption kinetics indicated that humic acid adsorption follows pseudo-second-order model (R2=0.9822). The results indicated that the cotton adsorbent coated with graphene oxide has a good potential for removal of humic acid from aqueous solutions. Mechanical flexibility, availability, and low operational energy costs are among the advantages of this method for fabrication of this adsorbent, which can be developed and used for reducing environmental contaminants.
Mansour Baziar,Ramin Nabizadeh,Amir Hossein Mahvi,Mahmood Alimohammadi,Kazem Naddafi,Alireza Mesdaghinia,Hassan Aslani 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.5
4-Chlorophenol (4-CP) is a hazardous and toxic chemical that enters into water bodies mainly through industrial effluents. The present study investigated the effect of under pressure dissolved oxygen on 4-CP degradation in the presence of nanoscale zero-valent iron (nZVI) and sodium persulfate. The impact of oxygen pressure, as a qualitative variable at three levels (1, 1.5 and 2 atm), along with five quantitative variables, including persulfate concentration (0-2mM), nZVI dosage (0-1 g/L), pH (3-11), reaction time (5-90min) and 4-CP concentration (50-500mg/L) on the 4-CP elimination from aqueous solutions, was examined using response surface methodology. There was a direct relationship between the dissolved oxygen under pressure and the 4-CP removal efficiency. Also, the gained R2 and adjusted R2 for three developed models of 1, 1.5 and 2 atm oxygen pressure were 0.971 and 0.9569, 0.9689 and 0.9538, and 0.9642 and 0.9468, respectively. The best removal process conditions for pH 4.2, 1.6mM persulfate, 64.79 min reaction time, 97.89mg/L initial 4-CP and 1 g/L nZVI dosage. The results indicated that dissolved oxygen under pressure- nZVI-persulfate could be considered a promising process for elimination of organic compounds from aqueous solutions.
Mohammad Hadi Dehghani,Masoome Mostofi,Mahmood Alimohammadi,Gordon McKay,Kaan Yetilmezsoy,Ahmad B. Albadarin,Behzad Heibati,Mohammad Al Ghouti,N.M. Mubarak,J.N. Sahu 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.35 No.-
The adsorption capabilities of two nano-sized adsorbents: multi-walled carbon nanotubes (MWCNTs)and single-walled carbon nanotubes (SWCNTs) were investigated for the removal of toxic phenol. Themaximum adsorption capacities of MWCNTs and SWCNTs were determined as 64.60 and 50.51 mg/g,respectively. Adsorption kinetics followed the pseudo-second order model for both adsorbents. Theoptimum conditions using SWCNTs and MWCNTs were pH 6.57 and 4.65, phenol concentration 50 and50 mg/L, dose 1.97 and 2 g/L and contact time 36 and 56 min, respectively. The results indicated thatMWCNTs and SWCNTs were proven as high-performance adsorbents for toxic phenol removal fromwastewater.
Mohammad Hadi Dehghani,Ahmad Zarei,Alireza Mesdaghinia,Ramin Nabizadeh,Mahmood Alimohammadi,Mojtaba Afsharnia 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.3
Arsenic contamination, a worldwide concern, has received a great deal of attention due to its toxicity and carcinogenicity. In the present study, we focused on the combined application of modified bentonite and chitosan (MBC) for the removal of As(V). Arsenic removal experiments were carried out to determine the amount of As(V) adsorbed as a function of pH (2-8), sorbent dosage (0.1-1.5 g/L), As(V) concentration (20-200mg/L) and time (60-240 min). The system was optimized by means of response surface methodology. The analysis of variance (ANOVA) of the quadratic model demonstrated that the model was highly significant (R2≈97.3%). Optimized values of pH, sorbent dosage, initial As(V) concentration and time were found to be 3.7, 1.40 g/L, 69mg/L, and 167min, respectively. The results reveal that the prepared adsorbent has a high adsorption capacity (122.23mg/g) for As(V) removal. Among the isotherm models used, the Langmuir isotherm model was the best fit for the obtained data. The adsorption kinetics following a pseudo-second-order kinetic model was involved in the adsorption process of As(V). Thermodynamic studies confirmed the spontaneous and endothermic character of adsorption process.