Journal of Applied Research in Chemical-Polymer Engineering

Abstract Research subject: In this study, Fe₃O₄ nanoparticles were first synthesized through a controlled co-precipitation method. Subsequently, a uniform silica coating was formed on the surface of iron oxide nanoparticles via the Stöber process using tetraethyl orthosilicate (TEOS) as the silica precursor, resulting in core–shell Fe₃O₄@SiO₂ nanoparticles with a stable and well-organized structure. The obtained nanoparticles were then functionalized with a molecularly imprinted polymer (MIP) to produce a targeted and selective adsorbent for the removal of zinc ions (Zn²⁺) from aqueous solutions. The concentration of Zn²⁺ ions was determined using Inductively Coupled Plasma (ICP) analysis.
Research approach: To comprehensively investigate the physical, chemical, and structural characteristics of the synthesized nanoadsorbent, various analytical techniques were employed, including transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR).
Main results: The characterization results confirmed the formation of a coherent structure with uniform particle size distribution, good thermal stability and successful incorporation of active functional groups on the nanoparticle surface. The adsorption performance of the nanoadsorbent for Zn²⁺ ions was evaluated by studying the effects of various operational parameters, including adsorbent dosage, contact time, pH and initial metal ion concentration. Optimized results revealed that under the conditions of an adsorbent dosage of 16 mg, pH=7, an initial concentration of 0.45 mmol L⁻¹, a solution volume of 50 mL, and a contact time of 21 min, the removal efficiency of Zn²⁺ ions reached 96%, indicating the high performance of the adsorbent (107.55 mg/g). Also, isotherm studies demonstrated that the adsorption process followed the Langmuir model, suggesting a monolayer adsorption mechanism. Furthermore, kinetic analysis showed that the experimental data fitted the pseudo-second-order model, confirming that chemisorption was the dominant rate-controlling mechanism. In addition, the synthesized nanoadsorbent exhibited excellent magnetic separability, allowing for easy recovery from the aqueous solution. It also demonstrated high reusability over multiple adsorption-desorption cycles without significant loss in its adsorption performance. Therefore, the designed adsorbent can be considered a stable, efficient, and environmentally friendly system, offering a promising approach for the effective treatment of industrial wastewater containing heavy metal ions.

Abstract Research subject: The scarcity of freshwater resources and the rapid growth of population have made the development and deployment of efficient desalination technologies an undeniable necessity for securing reliable supplies of drinking and industrial water. In this regard, the present study focuses on the modeling, validation, and techno-economic assessment of two widely applied technologies, reverse osmosis (RO) and multi-effect distillation (MED), as well as their integration in standalone and hybrid configurations.
Research approach: In the modeling stage, the key components of each process, including pumps, pressure exchangers, pretreatment units, and main desalination modules, were simulated with high accuracy using established mathematical correlations. Calibration and validation were carried out with the aid of WAVE software and field data from existing industrial plants, ensuring consistency between simulation results and practical operation. Four configurations, including RO, MED, RO-MED, and MED-RO, were investigated under identical feedwater conditions (50,000 m³/day, salinity of 30,000 mg/L) and defined operational constraints. The evaluation criteria included product water quality, recovery ratio, electrical and thermal energy consumption, and specific water production cost.
Main results: The results showed that, among the four standalone and hybrid RO and MED scenarios, the standalone RO system had the lowest levelized cost of water at 0.386 USD/m³, making it the most economical option. Its cost was about 38%, 19%, and 58% lower than MED, RO-MED, and MED-RO, respectively. In contrast, the product water quality of RO was 93%, 42%, and 47% lower than these alternatives. Sensitivity analysis revealed that increasing electricity price raised the cost of standalone RO by up to 78%, while higher fuel cost increased the MED cost by 85%. Moreover, variation in the interest rate had the strongest impact on MED-RO, raising its cost by up to 40%. In addition, the RO-MED hybrid configuration proved to be an economical alternative compared with other options, while ensuring higher water quality. These findings highlight that the optimal choice of technology strongly depends on local conditions such as energy price, availability of waste heat, and required product quality.

Abstract Research subject: Contact lens-based drug delivery is expected to be more efficient due to sustained release of drug and increased residence time in the tear film. In particular, hydrogel has been applied in contact lenses due to impressive function such as biocompatibility, wettability and optical transparency. Nevertheless, hydrogel lenses suffer from low oxygen permeability. To reduce the shortage of oxygen supply, the silicone-based polymers were used to improve the oxygen permeability. Vitamin E as a diffusion barrier could be introduced into silicone hydrogel contact lenses to extend drug release due to its lipophilic barrier.
Research approach: In this research, poly(3-(methacryloyloxy)propyltris(trimethyl-siloxy) silane-co-2-hydroxyethyl methacrylate) (poly(TRIS-co-HEMA)) copolymers were synthesized in order to evaluate the potential of these copolymers to be used as contact lens materials. The obtained copolymers were characterized using Fourier transform infrared spectroscopy, transmittance analysis, contact angle measurement and water content. The vitamin E was incorporated into copolymer films and the effect of vitamin E loading on extended drug delivery for diclofenac sodium were examined.
Main results: The equilibrium water content (EWC) of the synthesized poly(TRIS-co-HEMA) copolymers were proportional to the hydrophilic PHEMA content. The maximum value of surface hydrophilicity was 56.4°, corresponding to an equilibrium water content of 39%. Poly(TRIS-co-HEMA) films exhibited high transparency in the visible light wave range. Incorporation of vitamin E did not have significant impact on the wettability, EWC and transparency of the copolymer films. The results showed that with vitamin E loading in the copolymer film, the diclofenac release time could be increased to 90 h, which was a 3 fold increase compared to the diclofenac release duration by copolymer film without vitamin E loading. The vitamin E loaded poly(TRIS1-co-HEMA8) copolymer films could be very useful vehicles for extended drug delivery of diclofenac.

Abstract Research subject: Solar desalination based on interfacial evaporation has emerged as a promising strategy for mitigating global freshwater shortages due to its high solar-to-vapor conversion efficiency, low environmental footprint, and suitability for remote or off-grid deployment. However, salt accumulation at the evaporation interface, particularly from highly soluble species, significantly reduces vapor generation and undermines long-term system stability. Therefore, developing self-cleaning structures capable of maintaining continuous water transport while preventing salt crystallization is essential for practical field operation.
Research approach: This study develops a self-cleaning solar evaporator based on engineered sycamore wood and systematically evaluates its desalination performance. For this purpose, four systems are designed and fabricated, including a reference sample without artificial channels and three systems incorporating vertical channels with diameters of 1.0, 1.5, and 2.0 mm, which are evaluated under controlled one-sun irradiation using NaCl solutions representative of seawater (3.5 wt.%) and highly saline water (20 wt.%). Water transport behavior, ion migration mechanisms, and condensate quality are assessed through continuous evaporation experiments and ion concentration analyses for Na⁺, Mg²⁺, K⁺, and Ca²⁺. Additionally, operational stability is examined through multi-cycle repeatability tests.
Main results: The WSE-1.5 device exhibits the highest steady evaporation rates, achieving 2.48 and 2.04 kg.m⁻².h⁻¹ in 3.5 wt.% and 20 wt.% NaCl solutions, respectively. This favorable performance is attributed to the ion exchange between the natural microchannels of the wood, which contain higher concentrations of salt ions, and the drilled millimeter-scale channels with lower concentrations. The difference in hydraulic conductivity between these pathways drives salt migration from the millimeter-scale channels to the microchannels and subsequently into the bulk water. The engineered structure also maintains timely water replenishment at the evaporation surface, ensuring stable vapor production. The condensate quality meets World Health Organization (WHO) and Environmental Protection Agency (EPA) potable water standards, with significantly reduced concentrations of Na⁺, Mg²⁺, K⁺, and Ca²⁺. Repeatability tests confirm that WSE-1.5 retained its performance after 15 cycles with negligible degradation. Overall, the proposed wood-based evaporator offers an efficient, robust, and cost-effective solution for desalinating saline waters in challenging environments.

Abstract Research subject: Foaming is one of the major challenges in natural gas sweetening units, as it can lead to reduced absorption efficiency and serious operational problems. Blended amine solutions have emerged as a promising approach to improve the performance of CO₂ absorption systems. Despite extensive studies on single amine solvents, the foaming behavior and CO₂ absorption performance of blended systems containing methyl diethanolamine (MDEA) and 1,3-diaminopropane (DAP) have not yet been comprehensively investigated. In particular, the mutual effects of these two amines on foaming characteristics and absorption capacity remain insufficiently understood.
Research approach: The main objective of this study was to investigate the foaming behavior and CO₂ absorption performance of MDEA–DAP-blended solutions and to determine optimal operating conditions. Blended solutions were prepared at three total amine concentrations (23, 31.5, and 40 wt.%) with three different MDEA-to-DAP ratios. All experiments were conducted at 30 °C. Nitrogen gas was injected into the foaming apparatus at a constant flow rate of 1.5 L/min, and foam volume and foam break time were measured. CO₂ absorption experiments were carried out at a pressure of 620 kPa, and both absorption capacity and absorption kinetics were evaluated for all solvent compositions.
Main results: The results indicated that both foaming behavior and absorption performance are strongly dependent on total amine concentration and the MDEA-to-DAP ratio. Due to its tertiary amine structure, MDEA was identified as the primary contributor to foaming. In contrast, DAP, owing to its two primary amine groups, played a key role in enhancing CO₂ absorption capacity at a total concentration of 31.5 wt.% with 5 wt.% DAP, the best balance between reduced foaming and high absorption capacity was achieved, corresponding to a foam volume of 318.45 mL, a foam break time of 6 s, and an absorption capacity of 0.927 mol CO₂ per mol amine. The optimal condition was identified as a blend containing 26.5 wt.% MDEA and 5 wt.% DAP at a total amine concentration of 31.5 wt%, which is recommended for industrial CO₂ absorption applications.