APPLIED RESEARCH IN CHEMICAL POLYMER ENGINEERING
Year:2019 | Volume:3 | Issue:1 |Papers Count:6

Research Subject: In this paper, the adsorbents used to remove lead ion using adsorption operation have been reviewed. Research Approach: The types of adsorbents used to remove lead ions, the modifications of adsorbents, adsorption conditions, isotherms and adsorption capacity of adsorbents have been inves tigated and compared based on the literature survey. Main Results: Modification by impregnation of functional groups has a significant role in increasing the adsorption capacity. The pH of the solution plays an important role in the adsorption of lead ions and generally the adsorption capacity increases by increasing the pH of the solution. Langmuir’ s isotherm model has been more consis tent with the equilibrium data. Among the reviewed adsorbents, carbon-based adsorbents such as activated carbon and graphen-oxide, modified by chemicals such as ammonium persulfate or polyamines, show higher adsorption. Also, biomasses due to their abundance and low prices have the potential to be used as lead ion adsorbents.

Research Subject: Sulfide removal from sour water is essential, before reuse or release of sour water into the environment. Regarding the high costs of traditional methods, biological removal can be used as a reliable alternative. Research Approach: Biological sulfide removal from sour water was investigated in a batch reactor using Thiobacillus sp. as a dominant species of a mixed culture. A conceptual model was developed to describe the process of H2S removal from sour water in the batch reactor. The model considers H2S and O2 transfer between liquid and gas phases, biological oxidation of H2S to sulfate and elemental sulfur, and chemical oxidation of H2S to thiosulfate in the liquid phase. The governing equations were derived using the principles of mass conservation and biochemical reactions. Several batch runs were performed to obtain experimental data on the variation of sulfide, sulfate, thiosulfate, and oxygen concentrations in the sys tem as a function of time, and an algorithm was devised to use the method of Particle Swarm Optimization together with the numerical solution of the model equations to es timate biokinetic parameters. Additional batch runs under different conditions were performed to verify the accuracy of the model. These results indicated reasonable accuracy of the model to predict the performance of a batch reactor for the removal of H2S from sour water. The novelty of this model is considering different pathways for sulfide oxidation which includes product selectivity. Main Results: The maxim specific oxygen uptake rate (SOUR=OUR/X) is one of the mos t important parameters in the evaluation of the biological activity of the microorganisms. The calculated value for this parameter was almos t constant (16 mg DO g-1 VSS min-1) during all sulfide oxidation tes ts indicating that the maximum specific oxidation capacity of the biomass is independent of substrate and biomass concentration. Results exhibited bacteria prefer to partially oxidized sulfide to elemental sulfur, however this preference is a function of dissolved oxygen and subs trate availability.

Research subject: In recent years, many attempts have been devoted to industrial usage of biobased adhesives, as a result of fossil resources shortage and unusual increase in oil-based products prices. Adhesion s trength of this category of adhesives, however, needs improvement. Research approach: In the current s tudy, lap-shear s trength of joints made of a natural polymer, Persian gum (PG), exuded from wild almond tree, and three various substrates, glass, poly(ethylene terephthalate), and cellulose fabric, was inves tigated. Furthermore, in order to prepare powder acrylic adhesive and evaluate its adhesion to aforementioned subs trates, the gum dispersion was blended with synthesized poly(methyl methacrylate-co-butyl acrylate) random copolymer containing 30 wt. % methyl methacrylate (MBC30). Molecular interactions in PG, MBC30, and 50 wt. % PG-containing blend were characterized by Fourier transform infrared spectroscopy. Moreover, morphology of blends containing various amounts of PG was evaluated using scanning electron microscopy of their fractured cross sections. Main results: The textile joint made with PG dispersion in water showed high shear s trength of about 340 kPa. However, PG could not form a suitable joint with glass and polyester subs trates, as a consequence of its inability to form a homogeneous film, excessive brittleness, and its inability to diffuse and mechanically interlock with the subs trates. Results showed that using an adhesive sys tem containing 50/50 PG/MBC30, besides enabling preparation of powder adhesive, shear s trength increased to 20, 11, and 14-fold with respect to pris tine MBC30 on glass, poly(ethylene terephthalate), and textile subs trates, respectively. In other words, shear strength of an adhesive could be improved by promoting the adhesive cons tituents interactions and subsequent increase in the blend cohesiveness, on the one hand, and increment of its adhesion to subs trate, on the other hand. In the current research, Persian gum was introduced as a water-redispersing agent for acrylic pressure-sensitive adhesives and new adhesive sys tems were invented with usability in cellulose indus try.

Research Subject: Removal of indus trial was tewater especially from textile and dyeing factories is always important actions to control of pollutions. Using of polymeric adsorbents is an important method for removal of dyes from indus trial was tewater. In this research work, designing and fabrication of PVA-based adsorbent with proper potential for removal of green malachite from indus trial was tewater has been reported. Research Approach: For fabrication of adsorbent 4 wt. % PVA was gelled in the present of 10 wt. % glutaraldehyde as cross-linker and punched. The punched hydrogels were porous with freeze drying method. For improving the adsorption ability, graphene and TiO2 were used. The adsorption of green malachite with prepare adsorbent was measured timely to determine the optimum percentage of nanoparticles. In addition, the effect of contact time and the presence of UV on the adsorption of pollution was inves tigated. Finally, the adsorption isotherms and thermodynamics study were inves tigated in different time. Main Results: The results of adsorption of pollution with PVA/graphene adsorbent in different times showed that 0. 5 wt. % is the optimum loading of graphene in the PVA matrix. This value was 3 wt. % for TiO2. The adsorption percentage via optimum adsorbent in dark condition showed that one minute after addition of adsorbent the adsorption percent increased to 75% indicating the high capability of the adsorbent in adsorption of tested pollution. The porous s tructure was confirmed via SEM image. By comparing the correlation coefficient for Langmuir and Freundlich isotherms it was found that Freundlich isotherm has better agreement with the findings of the current s tudy. In other words, adsorption of green malachite with fabricated adsorbent was done multi layered. The thermodynamics s tudies showed that due to negative value of Gibbs energy the adsorption reaction of green malachite with fabricated absorbent is automatically.

Research Subject: Nowadays, application of biosurfactants in microbial enhanced oil recovery (MEOR) have aroused much attention and several inves tigations have been conducted on this field. But their performance in comparison to synthetic surfactants in enhanced oil recovery has little been s tudied. Mos t of these researches are limited to comparison of one produced biosurfactant with only a chemical surfactant. To fill this gap, in this research, the potential use of a rhamnolipid type biosurfactant in MEOR was compared to several conventional synthesized surfactants: SDS, SDBS, CTAB and DTAB. Research Approach: Since the main goal of this research is the comparison between produced biosurfactant and conventional chemical surfactants in oil recovery, several flooding tests were conducted and involved mechanisms were inves tigated. All of tes ts were conducted in an oil wet glass micromodel saturated with heavy oil at ambient condition. Injected solutions were prepared at critical micelle concentration of surfactants. During the flooding tes ts, high quality pictures were taken with a camera connected to the computer to monitor the motion of injected solution in the micromodel. Main Results: 40% oil recovery was achieved after biosurfactant flooding while SDBS, SDS, CTAB and DTAB resulted 36%, 34%, 32% and 29% oil recovery, respectively. For mechanis tic s tudy, the surface tension (ST) and viscosity measurements were performed and contact angle was determined. The surface tension reduction, wettability alteration towards more water-wet condition and increasing the ratio of injected fluid viscosity to oil viscosity were dominant mechanisms. The rhamnolipid was more effective than other surfactants in reduction of surface tension and altering the wettability towards favorable water-wet conditions. It decreased the surface tension of water from 72 to 28 mN/m, which was the leas t comparing to other surfactants and increased the capillary number about 19. 4 times greater than in water flooding. Additionally, it changed the contact angle from 106 to 6, 94. 3%, the wides t change among applied surfactants.

Research Subject: Other waste incinerators and other high-temperature sys tems designed to dispose of garbage are referred to as heat treatment sys tems. The burning of was te materials, such as garbage, converts them into ashes collected on the waste floor, exhaus t gases, very small particles and, mos t importantly, heat, which can be used to generate electrical power. Research Approach: In this research, firs tly, the energy and exergy efficiencies of a was te incineration cycle, along with utilization of Lorestan petrochemical waste as an additional fuel for was te incineration, are inves tigated. In this way, the amount of energy needed to produce the required water vapor to disable the catalys t Ziegler-Nata was calculated for the production of linear s tylis tic polyethylene. Subsequently, a simple model for the inactivation reaction of Ziegler-Nata catalys ts was presented using the s team generated by the was te incinerator, and then the mathematical equations for these reactions were obtained using the primary reaction law. By introducing these reactions into the reaction model, a new equation for the reaction model was obtained that covers the moments after the time of deviation to an acceptable level. This indicates the overcoming of inactivation reactions on the reactions of active centers production in the final s tages of the reaction. Main Results: The energy and exergy efficiencies of the was te incineration cycle along with the use of Lores tan petrochemical was te as an additional was te gas were inves tigated and thus the amount of energy needed to generate s team to disable Natal Ziegler catalys ts in the production of linear linear polyethylene was calculated. To initiate this, the combined cycle was proposed and its energy and exergy efficiencies were inves tigated. Also, by changing the key components such as the ammonia solution composition, the ammonia dis tillation temperature and the input and output pressures of turbine, a way to achieve the energy needed to generate the s team needed to deactivate the Nitra zigzag catalys t in the production of linear linear polyethylene was developed.