Journal of Applied Research of Chemical -Polymer Engineering

Abstract Research subject: Oil-based wastewater treatment is essential to prevent environmental harm and comply with regulations. Membrane processes are ideal for this due to their efficiency, low energy use, and ability to handle complex emulsions effectively.
Research approach: The primary goal of this study is to employ an ultrafiltration membrane separation process for the treatment of wastewater containing oil compounds (e.g., diesel fuel). To achieve this, polyethersulfone/sulfonated-polyethersulfone (PES/SPES) blend membranes with various SPES loadings were fabricated using the nonsolvent-induced phase separation (NIPS) method. The effects of SPES loading on the membrane morphology, surface roughness, surface hydrophilicity, mechanical strength, porosity, and water and wastewater flux were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle measurement, mechanical strength testing, and filtration performance tests, respectively.
Main results: The results showed that adding SPES to PES and increasing the loading of SPES led to the formation of macrovoids in the membrane cross-section, enhanced surface roughness and hydrophilicity, increased porosity, improved water and wastewater flux, and increased the pure water flux recovery ratio. However, these benefits came with reduced mechanical strength and increased membrane compaction. Among the prepared membranes, the PES/SPES (60/40 wt./wt.) blend membrane exhibited the best filtration performance, achieving a final wastewater flux of 34.78 L/m²·h, compared to 11.35 L/m²·h for the neat PES membrane. Meanwhile, the PES/SPES (40/60 wt./wt.) composite demonstrated the highest surface roughness, hydrophilicity, and flux recovery ratio. Notably, all membranes synthesized in this study achieved over 99% rejection efficiency for the diesel fuel-water emulsions, which is significant for practical and industrial applications.

Abstract Research subject: In recent decades, water and gas injection have gained significant attention for enhancing oil recovery. However, some engineers believe that alternative methods can play a more pivotal role in this field. The use of surfactants is considered an innovative technique that has had a notable impact on the oil industry. Nevertheless, the large-scale production of such materials is financially costly. Additionally, their synthesis results in the generation of toxic and hazardous waste, posing various threats to human health and the environment, ultimately leading to widespread and irreparable pollution. The use of natural surfactants has emerged as a viable solution with relatively high efficiency. These natural surfactants are extracted from the leaves of native plants, offering a cost-effective approach. Moreover, they are biodegradable and pose no risks to human health or the environment.
Research approach: The combination of these natural surfactants in oil-related experiments has yielded satisfactory results, demonstrating their effectiveness in reducing interfacial tension between water and oil, as well as modifying the viscosity of crude oil. This study specifically examined the interaction between surfactants and divalent ions at their lowest concentrations. One of the testing processes involved injecting these solutions into a micromodel, which was subsequently analyzed.
Main results: The combination of these surfactants with divalent ions and crude oil significantly reduced interfacial tension. Notably, the combination of Morus leaf extract with calcium ions reduced the interfacial tension of crude oil to 15.6 mN/m, while Citrus extract with sulfate ions reduced it to 13.6 mN/m. Additionally, in many viscosity tests, a reduction in crude oil viscosity was observed. The combination of calcium ions with Morus extract resulted in approximately 41% oil recovery, whereas sulfate ions with Citrus extract led to a 50% final recovery rate.

Abstract Research subject: In the present study, Fe₃O₄@SiO₂ nanoparticles functionalized with polymer dendrimer molecules are synthesized by the Stöber method. The synthesized nanostructure is applied as a recognition element in the structure of a carbon paste electrode for monitoring copper ions from aqueous solutions and real samples of the cooling tower of a thermal power plant.  One of the main applications of this sensor is as a key condition monitoring method for measuring copper ions in industrial cooling towers.
Research approach: The surface chemistry, particle size, and morphology of the synthesized nanoparticles are evaluated using transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometer, thermal weighing analysis, and energy dispersive X-ray spectroscopy. In order to optimize the performance of the copper ion monitoring sensor, parameters such as graphite percentage, paraffin, and detector composition are evaluated.

Main results: The highest sensor response is achieved at 75% graphite, 20% paraffin, and 5% nanostructure percentage. The behavior of copper ions is investigated using cyclic voltammetry, and an oxidation peak is obtained at 0.2 V region for copper oxidation. The obtained sensor has a detection limit of 10^-5 M and a linear range of 0.1-1 mM in differential pulse voltammetry. The proposed sensor is capable of application in real complex samples, such as a power plant cooling tower water. The results of the presented method are in agreement with the atomic absorption reference techniques. The proposed method is able to measure copper ions in a cooling tower sample with high accuracy and precision.
 

Abstract Research subject: The formulation of sublimation inkjet inks based on disperse dyes requires precise control of dispersion stability and rheological behavior to achieve consistent print quality and printer compatibility. One of the main challenges in this field is establishing an appropriate balance between polymeric dispersants and low-molecular-weight surfactants to prevent sedimentation, viscosity fluctuations, and surface tension instability. This study investigates the influence of nonionic surfactant concentration on the physical characteristics, dispersion stability, and rheological behavior of Disperse Blue 359 in aqueous sublimation inkjet ink formulations.
Research approach: Dye concentrates were prepared using a jar mill in the presence of a polymeric dispersant, glycerol, and deionized water. The concentration of the nonionic surfactant was varied from 0 to 7.1 wt%. The samples were characterized in terms of color strength by UV-vis spectrophotometry, particle size by dynamic light scattering, surface tension by the Wilhelmy method, and rheological behavior by a rotational rheometer. Dispersion stability was also monitored by turbidity measurements over different time intervals.
Main results: The results revealed that the simultaneous presence of the polymeric dispersant and the nonionic surfactant significantly improved the stability and flowability of the system. Specifically, the sample with the optimally concentrated surfactant exhibits turbidity oscillation of less than 30 NTU and a viscosity below 8.5 cp, while the surfactant-free sample experiences a turbidity reduction exceeding 500 NTU over the test duration and a viscosity above 17 cp. At an optimal surfactant concentration of approximately 3.6 wt%, the particle size reached its minimum, color strength reached its maximum, and dispersion stability was maximized. Conversely, both higher and lower surfactant concentrations led to particle aggregation, increased turbidity, and diminished print quality. These findings highlight the critical importance of accurately tuning the ratio of surfactant to dispersant in designing reliable sublimation inkjet inks with desirable optical and rheological properties.