Removal of Penicillin G from aqueous medium by PPI@SBA-15/ZIF-8 super adsorbent: Adsorption isotherm, thermodynamic, and kinetic studies.

In the present paper, synthesis of SBA-15 nanoparticles was carried out from tetraethyl orthosilicate (TEOS) precursor using the sol-gel process. After being combined with Poly propylene imine, and ZIF-8 they were employed for the removal of Penicillin G. The synthesized combination morphology was assessed using nitrogen adsorption and desorption (BET), Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffraction (XRD). The parameters affecting Penicillin G removal, including pH, amount of adsorbent, time of contact, temperature, and concentration, were optimized, and the optimum levels of the mentioned variables were reported to be pH = 3, 0.03 g, 90 min, 25 °C, and 100 ppm, respectively. In addition, application of Freundlich, Langmuir, Dubinin-Radushkevhch, and Tempkin models and pseudo-first-order and pseudo-second-order adsorption synthetic equations aimed at determining the type of adsorbent isotherm. The results showed that the best fitting of Langmuir (R2 = 0.9944, qm = 400 mg/g) for adsorption isotherm and pseudo-second-order model (R2 = 0.9905) for kinetics studies. Furthermore, data of Gibbs free energy and enthalpy demonstrated an exothermic and spontaneous process in the research.

Enhancing toxic gas uptake performance of Zr-based MOF through uncoordinated carboxylate and copper insertion; ammonia adsorption.

This study reports the development of a new type of Zr-based MOF by inserting copper and carboxylate into HCl modulated UiO-67 (UiO-67-vac) which gained higher surface area/vacant than UiO-67. Copper was inserted into MOF containing uncoordinated carboxylate group, to create open metal site in the form of -COOCu which called UiO-67-ox-Cu. PXRD, FTIR, BET, SEM, EDS, UV-Vis and XPS were used to characterize the obtained MOFs. As expected, UiO-67-ox-Cu exhibits the highest ammonia capacity (178.3 mg/g) among UiO-67 (104 mg/g) and UiO-67-vac (121 mg/g) at 298 K and 1 bar pressure. In fact, the significant increase in ammonia uptake of UiO-67-ox-Cu is related to the modified binding affinity of -COOCu groups with ammonia. Moreover, UiO-67-vac with the highest surface area showed the hydrogen adsorption capacity of 18.75 mg/g at 77 K, which is comparable or even superior to the previously reported value. Interestingly, adsorption capacities were retained with slight changes around five cycles and three regeneration temperatures, 25, 60 and 120 °C under vacuum pressure which were proved by PXRD after ammonia adsorption/desorption. The good results obtained in the current work clearly show the role of postsynthesis functionalization approach for creation of new metal/active sites into MOFs.

Adaptive Neuro-Fuzzy Inference system analysis on adsorption studies of Reactive Red 198 from aqueous solution by SBA-15/CTAB composite.

In this study, the Mesoporous material SBA-15 were synthesized and then, the surface was modified by the surfactant Cetyltrimethylammoniumbromide (CTAB). Finally, the obtained adsorbent was used in order to remove Reactive Red 198 (RR 198) from aqueous solution. Transmission electron microscope (TEM), Fourier transform infra-red spectroscopy (FTIR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD), and BET were utilized for the purpose of examining the structural characteristics of obtained adsorbent. Parameters affecting the removal of RR 198 such as pH, the amount of adsorbent, and contact time were investigated at various temperatures and were also optimized. The obtained optimized condition is as follows: pH=2, time=60min and adsorbent dose=1g/l. Moreover, a predictive model based on ANFIS for predicting the adsorption amount according to the input variables is presented. The presented model can be used for predicting the adsorption rate based on the input variables include temperature, pH, time, dosage, concentration. The error between actual and approximated output confirm the high accuracy of the proposed model in the prediction process. This fact results in cost reduction because prediction can be done without resorting to costly experimental efforts. SBA-15, CTAB, Reactive Red 198, adsorption study, Adaptive Neuro-Fuzzy Inference systems (ANFIS).

The polythiophene molecular segment as a sensor model for H2O, HCN, NH3, SO3, and H2S: a density functional theory study.

Studying the interaction of some atmospheric gases (H2O, HCN, NH3, SO3 and H2S) with 3PT oligomers is important in the development of polymeric sensors for gas detection. In the present study, we studied the relaxed geometries, interaction energies, charge analysis, HOMO-LUMO orbital analysis, and UV-vis spectra of all interacted systems using first-principles density functional theory (DFT). All these analyses indicated the potential of polythiophene as an inexpensive polymeric sensor for the analytes mentioned. Interaction energy values of -19.90, -19.66, -14.01, -8.70, and -4.76 kJ mol(-1) were achieved for adsorption of SO3, H2O, NH3, HCN, and H2S on 3PT, respectively. Consequently, clarification of their physical parameters became the major focus of this study.