Phosphorene and Na-, Ca-, and Fe-doped phosphorene as candidates for delivery of mercaptopurine and fluorouracil anticancer drugs.

Phosphorene ability for delivery of mercaptopurine and fluorouracil was investigated by the density functional theory (DFT) method. However, the effects of Na, Ca, and Fe as dopants on phosphorene electronic properties such as HOMO and LUMO energies, density of states, chemical potential, electrophilicity index, softness, hardness, and its ability for drug delivery were studied. Natural bond orbital (NBO) analysis was performed. Our findings indicate that metallic dopants can improve the ability of phosphorene. Calcium-doped phosphorene has the greatest adsorption energy.

Application of polyamide thin-film composite layered on polysulfone-GO/TiO2 mixed matrix membranes for removal of nitrotoluene derivatives from petrochemical wastewaters.

Release of harmful organic intermediates or byproducts during the manufacture of petrochemical compounds is a serious problem in petrochemical plants. In this work, polysulfone membranes blended with GO/TiO2 nanocomposite were synthesized by phase inversion method and coated with a polyamide layer formed by interfacial polymerization to prepare a thin-film composite (TFC) sample. Analysis and characterization of the sample were carried out by XRD, FE-SEM, BET, FTIR/ATR, AFM, TGA, and zeta potential. Results indicated that incorporation of GO/TiO2 into the membrane structure enhanced porosity, surface roughness, and macrovoid formation along the cross-section of the sublayer and permeability of the membrane. The TFC membranes were applied to remove mononitrotoluene (MNT) and dinitrotoluene (DNT) as the basic intermediates of toluene diisocyanate (TDI). The membranes demonstrated high efficiency (> 90%) for the removal of MNT and DNT according to the charge exclusion mechanism and Donnan effect. Application of the TFC membrane for treatment of wastewater in the TDI plant showed that the removal of pollutants is variable in the range of 45-65% and 53-69% for the membrane with the highest flux and highest rejection in different transmembrane pressure, respectively.

Removal of 2,4-D, glyphosate, trifluralin, and butachlor herbicides from water by polysulfone membranes mixed by graphene oxide/TiO2 nanocomposite: study of filtration and batch adsorption.

PURPOSE: Degradation or decomposition of the chemical herbicides by natural reagents after using can lead to produce various types of harmful intermediates. Ultrafiltration by the mixed matrix membranes blended with the graphene oxide/TiO2 can remove the residual herbicides from aqueous solution. METHODS: Graphene oxide/TiO2x% (x = 10, 30, 50%) was prepared by solvothermal method and blended by polysulfone to prepare GO/TiO2/PSf membranes for dynamic rejection of aqueous solutions of glyphosate, 2,4-D, butachlor, and trifluralin in a dead-end flow system. The blended membranes were also applied for the adsorption of herbicides in batch experiments. RESULTS: Addition of GO/TiO2 nanocomposite increased water flux from 7.3 for pure membrane to 211-326 kg/m2 h for mixed matrix samples in order to increase of the membrane porosity and surface hydrophilicity. The herbicides rejections were found in the range of 50-70% related to GO/TiO2 content. It was found that the membrane blended with 0.5 wt.% of GO/TiO2(10%) demonstrated the most efficiency. CONCLUSIONS: Details of dynamic filtration showed that the blended membrane acted based on the size exclusion mechanism. Adsorption experiments indicated that the strong attractions between H-bond donor sites of the herbicide and GO/TiO2 nanoparticles in membranes played a key role in the increase of adsorption of herbicides on the membrane.

Adsorption of light mercaptans over metal (Co, Cu, Fe, Ni) doped hexagonal boron nitride nanosheets: a first-principles study.

Light mercaptans (R-SH, R = C1-C4) as volatile malodorous and toxic compounds were theoretically adsorbed on metal (Co, Cu, Fe, Ni) doped hexagonal boron nitride (h-BN) nanosheets to obtain the adsorption energies of the mercaptans and electronic structures of the sheets before and after adsorption using the density functional theory method. The results indicate that doping B/N vacancy h-BN sheets with the metals decreased Eg compared to the pristine h-BN. Adsorption energies showed strong chemisorption of light mercaptans over metal doped h-BN. It is found that by increasing the alkyl chain in mercaptan the adsorption energy increases. Charge analysis and study of the correlation between variation of charge in the sulfur atom and the adsorption energy of mercaptan are presented.

Dynamic filtration and static adsorption of lead ions in aqueous solution by use of blended polysulfone membranes with nano size MCM-41 particles coated by polyaniline.

MCM-41 mesopore was prepared by hydrothermal method and used for synthesis of polyaniline/MCM-41 nanocomposite via in situ polymerization. The nanocomposite was blended with polysulfone to prepare mixed matrix membrane in different content of nanocomposite by phase inversion method. Structural and surface properties of the samples were characterized by SEM, XRD, FTIR, AFM, TGA, BET, and zeta potential measurements. Effect of the nanocomposite content on the hydrophilicity, porosity, and permeability of the membrane was determined. Membrane performance was evaluated for removal of lead ions in dynamic filtration and static adsorption. The membranes were found as effective adsorptive filters for removal of lead ions via interactions between active sites of nanocomposite in membrane structure and lead ions during filtration. Results of batch experiments proved adsorptive mechanism of membranes for removal of lead ions with the maximum adsorption capacity of 19.6 mg/g.