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Papers by abolfazl arjmandi

International Journal of Petrochemical Science & Engineering

In the present study, a new approach for determination of energy distribution (ED) of heterogeneo... more In the present study, a new approach for determination of energy distribution (ED) of heterogeneous solid adsorbents is presented. This approach implements pore size distribution (PSD) data of a porous adsorbent obtained from adsorption measurements to estimate the ED of the solid. Moreover, the proposed algorithm imposes some modifications on the conventional adsorption models to improve them and provide better prediction of adsorption behavior. Adsorption data of four different heterogeneous cases were used to evaluate the proposed algorithm. From the results, the proposed algorithm provided better estimation of adsorption isotherm than conventional adsorption models such as Unilan, Toth and Sips as well as easily calculated ED. The accuracy of the proposed algorithm is greatly depends on selection of appropriate PSD determination method. The proposed algorithm regarded as a trustworthy procedure for reliable estimation of ED of heterogeneous solid adsorbents.

Chemical Engineering Research and Design

Selenium Contamination in Water

To investigate the adsorption property of H2 and CO2 on the organic ligand of C-MOF-5 (H2BDC) and... more To investigate the adsorption property of H2 and CO2 on the organic ligand of C-MOF-5 (H2BDC) and T-MOF-5 (ZnO-doped H2BDC (ZnO-H2BDC)), Density functional theory (DFT) method was performed. First, the adsorption of ZnO on H2BDC resulted in examining binding energies, the charge transfer, density of states, dipole moments and adsorption geometries were investigated. The binding properties have been calculated and investigated theoretically for ZnO-doped H2BDC in terms of binding energies, band structures, Mulliken charges, and density of states (DOSs). According to obtained results, the H2BDC was strongly doped with ZnO. H2 and CO2 adsorption capacities for ZnO-doped H2BDC are significantly enhanced while there are low adsorption capacities for H2BDC. According to results, at least in the organic ligand of the MOF-5, the highest and lowest adsorption of CO2 (or H2) is attributed to the T-MOF-5 and C-MOF-5 respectively. Our calculations reveal that ZnO-doped H2BDC system (T-MOF-5) ha...

Journal of Water Process Engineering, 2020

The current experimental and theoretical study proposes forward osmosis (FO)-reverse osmosis (RO)... more The current experimental and theoretical study proposes forward osmosis (FO)-reverse osmosis (RO) (FR*) and FO-FO-RO (FFR) hybrid systems to combine concentration of cheese whey and Caspian seawater desalination. The powerful TF-PMM was used as a FO membrane. The impact of sales of concentrated cheese whey on reducing Caspian seawater desalination costs was studied. The results showed that the TF-PMM has good potential for concentration of cheese whey with a water flux of about 12.62 L/m 2 h. In terms of permeate concentration (Cp) and at low recovery rates (RR), the choice of FR* and FFR hybrid systems with 0.3 M NaCl as the draw solution (DS) should be the priority. At high RR, although the sensitivity of the type of system is reduced, the FR * system should not be used. The total power consumption (Est) for the FR*-30% and FR*-50% systems are lower than that of a single RO unit. In FR* hybrid system by increasing the RR FO1 , the power consumption of the FO unit and also the Est decreased. Also, in the FFR system, by increasing the concentration of the DS, while increasing the Est, the power consumption portion of the FO unit decreased. The existence of a valuable by-product in the proposed hybrid systems increases the allowable limit of the cost of required equipment and other operating costs to achieve profitability and reach the break-even point. In the meantime, the FR *-50% system generates the most revenue, and also the quality of produced freshwater from the FFR-50%-0.3M system is the highest.

Russian Journal of Physical Chemistry A, 2020

Cyanogen halides are a group of highly toxic and colorless compounds. Their presence in the envir... more Cyanogen halides are a group of highly toxic and colorless compounds. Their presence in the environment and direct contact with these compounds can be dangerous. So finding a reliable and accurate sensor for these compounds can be very beneficial. In this study, the adsorption of cyanogen halides (XCN, X = F, Cl, and Br) on 2PANI was investigated, using UB3LYP/6-31G*(d) as a DFT method. The binding energies between 2PANI and XCN were calculated. Also, Mulliken charge transfer (Q Mulliken), molecular electrostatic potential (MEP) and the global indices of activities were calculated and orbital analyses were performed. Based on our results, it can be found that at proper configuration the FCN, ClCN, and BrCN molecules can be adsorbed on 2PANI with adsorption energies (E ads) of-9.975,-11.025, and-26.510 kJ/mol, respectively. As a result, 2PANI can be used as a useful, portable, and cheap sensor for cyanogen halides.

Chemical Engineering Journal, 2020

Exploring the use of cheap natural raw materials to reduce the internal concentration polarizatio... more Exploring the use of cheap natural raw materials to reduce the internal concentration polarization in thin-film composite forward osmosis membranes,

Solid State Sciences, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Мембраны и Мембранные технологии, 2018

Desalination, 2020

The main reason for the lower water flux, than expected, in the forward osmosis (FO) process, is ... more The main reason for the lower water flux, than expected, in the forward osmosis (FO) process, is the internal concentration polarization (DICP). Usually, the structural parameter (S) is used as an indicator of the intensity of DICP. Small S value is desirable for the FO membrane due to the low DICP. However, due to design and construction problems, structural parameter reduction has some drawbacks. In this work, DICP reduction in FO membranes will be investigated using an approach other than structural parameter reduction. Accordingly, during the FO process, the feed solution (FS) valve is opened and closed at a constant period of time (feed valve timing (FVT)). Four types of FO membranes with different S parameters were used. The effects of the implementation of the proposed protocol on the water flux (J w), reverse salt flux (J s), specific reverse solute flux (J s /J w) and effective driving force were investigated. The effects of the S parameter and draw solution (DS) concentration also investigated separately. The results showed that the proposed protocol significantly increased J w. Also, the values of J s /J w decreased with increasing the FVT values and reached the lowest level in the practical recovery time (PRT).

Petroleum Chemistry, 2018

⎯In this study, cubic and tetragonal structures of MOF-5 (C-MOF-5 and T-MOF-5) were successfully ... more ⎯In this study, cubic and tetragonal structures of MOF-5 (C-MOF-5 and T-MOF-5) were successfully synthesized, characterized and incorporated into cellulose acetate (CA) polymer matrix in the range of 6, 9 and 12 wt % to fabricate mixed matrix membranes (MMMs). The effects of smaller pore size of T-MOF-5 and more ZnO molecules in T-MOF-5, on the H 2 and CO 2 permeation properties of C-MOF-5/CA and T-MOF-5/CA MMMs were investigated. The all novel MMMs were prepared using the solution casting method and characterized by FTIR, TGA and SEM. SEM images as well as results of FTIR and TGA analyses confirmed good adhesion between both MOF-5s and CA matrix. Addition of both C-MOF-5 and T-MOF-5 into the CA improved the gas transport properties of the CA, especially in H 2 separation. The H 2 /CO 2 selectivity continued the increasing trend at 9 wt % and did not significantly reduce even at 12 wt % due to good adhesion between both MOF-5s and CA. The highest H 2 /CO 2 selectivity was obtained at 12 and 9 wt % loading of C-MOF-5 and T-MOF-5, respectively. By changing the filler from C-MOF-5 to T-MOF-5, the increasing and reducing of adsorption site of H 2 and CO 2 (respectively), and also reducing in pore size, caused the appearance of H 2 permeability to not change much but the CO 2 permeability to reduce. Accordingly, the H 2 /CO 2 selectivity in all T-MOF-5/CA MMMs is higher than that in all C-MOF-5/CA MMMs. According to obtained results, the activated MOFs (i.e., C-MOF-5 in this study) are not always the best choices for separation process.