Case Studies in Chemical and Environmental Engineering最新文献

In full-scale units, the real application of nanoparticles photocatalytic degradation is still challenging due to the requirement of post separation for recovery of fine particles. This work investigated the removal efficiencies of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) using titanium dioxide (TiO₂) nanoparticles coupling with graphene oxide (GO) sheets immobilized in polyvinyl alcohol (PVA) matrix via solution-casting and a heat-treatment process to achieve the TiO₂/GO/PVA nanocomposite film as a photocatalyst. The operative parameters were focused on initial solution pH value, GO concentration, and heat-treatment time, which subsequently determined the optimal indices for the catalyst film. The structure characterization of the Ti–O–C bond indicated that a strong interaction between GO and TiO₂ had been formed at the hydrolysis process while TiO₂/GO nanoparticles were chemically embedded in PVA matrix by the heat-treatment method. The photocatalytic degradation of PFOS and PFOA produced a nanocomposite film with 25 wt% TiO₂/GO that was treated at 120 °C for 3 h and exhibited a remarkable removal activity in acidic solution with a pH of 3. This condition efficiently degraded PFOS and PFOA by approximately 95.99 % and 96.89 %, respectively, through a photocatalytic reaction. This research presents a straightforward method to synthesize TiO₂/GO/PVA catalyst that influences persistent organic pollutants (POPs) under ultraviolet irradiation, which is of practical significance for environmental applications.

The construction sector is responsible for 25 % of global greenhouse gas emissions and consumes 50 % of the world's energy. This paper addresses the use of nanomaterials in housing construction, comparing their influence at the technical-structural level. Materials such as titanium dioxide, carbon nanotubes, nanosilica, nanocellulose, nanoalumina, and nanoclays were analyzed. It was obtained that these nanomaterials can improve the structural, thermal, and functional properties of construction materials. In addition, they are related to increased durability, increased mechanical strength (>20 %), reduced thermal conductivity, and self-cleaning capability. Therefore, the use of nanomaterials promises to improve the sustainability and efficiency of housing construction.

Anthropogenic pressures on the environment are increasingly evident, characterized by uncontrolled changes in land use that adversely affect water quality. This study aims to assess how land use and land cover contribute to water quality and to evaluate the influence of spatial landscape metrics on water quality variability in eight tributary sub-basins of the Paraopeba River. The analysis considers two seasonal periods reflective of the region's tropical climate. The dataset includes spatial data on land use and land cover, digital elevation models, soil types, geology, geomorphology, spatial-temporal data, and landscape fragmentation metrics. First, spatial differences in water quality data collected at each sampling site were tested, and the significance of seasonal variations was assessed. Correlation analyses were then conducted to determine the relationships between landscape metrics and water quality parameters across the eight sub-basins, considering both seasonal periods. Key findings include the identification of mixed pollution sources, such as pasture, urban areas, and mining, which significantly affect water quality, particularly during the rainy period. Conversely, forest plantations were found to be the land use category that most positively contributed to the preservation of water quality. The relationships between landscape patterns and water quality, analyzed using redundancy analysis, revealed that the influence of landscape metrics on the variation of water quality parameters was significantly more pronounced during the dry period, explaining 75 % of the variation, compared to 49 % during the rainy period.

One of the predominant problems encountered by consumers in the Al-Gharab network in Al-Qadisiyah, Iraq, pertains to the issue of scheduled power interruptions due to the high gap between the generation and demand. The network also suffers from power losses and voltage deviations. This study aims to eliminate the issue of scheduled power interruptions by integrating Distributed Generation (DG) sources based on the available energy sources, which are Waste-To-Energy (WTE), in addition to the Photovoltaic (PV) sustainable source. The proposed system is simulated using the Open Distribution System Simulator (OpenDSS). The AutoAdd Optimization (AAO) technique was adapted to determine the optimal placement and size of the distributed generators. The findings indicated that the integration of WTE generation with solar PV plants result in power generation that is adaptable to variations in solar irradiation and fluctuations in demand, meeting roughly 50 % of the power demand in the Al-Gharab network throughout the day. This led to a 50 % decrease in the amount of electricity sourced from the national grid. Additionally, the outcomes of the simulation demonstrated that the suggested hybrid system improves network efficiency by reducing total active power losses, total reactive power losses, and voltage deviation index by 77 %, 42 %, and 87 %, respectively. The Homer Pro tool was used for the economic viability analysis. The findings exhibited a satisfactory economic feasibility. The Levelized Cost of Energy (LCOE) of the proposed system was found to be 0.0877 $/kWh, representing a 7.7 % reduction compared to the base case (without DG), with a simple payback period of 9.6 years.

The demand for efficient and sustainable gas separation technologies is ever-increasing in various industries, including petrochemicals, natural gas processing, and carbon capture. Polymer-based membranes offer a promising solution due to their potential for high selectivity and energy efficiency. However, achieving optimal gas separation performance often requires overcoming the limitations of individual polymers through modifications such as polymer blending. In this study, PSf/P84 blended membranes with low P84 content were fabricated using the phase separation technique with a mixture of N-methyl-2-pyrrolidone and tetrahydrofuran as solvents. The effect of varying the mass ratio of PSf to P84 on membrane characteristics and gas separation performance was investigated. Characterization techniques included FTIR, XRD, SEM, TGA, Water Contact Angle (WCA) measurement, and mechanical property testing. Gas permeation tests were conducted with single gases at room temperature and 1 bar pressure. The results revealed that the addition of P84 increased membrane thickness, Young's modulus, and thermal stability, while decreasing d-spacing, dense layer thickness, hydrophilicity, tensile strength, and elongation. The F_index values, indicating the competence of the blended membranes compared to the ideal quality, demonstrated the positive impact of P84 addition on gas separation performance compared to pure PSf membranes. The optimal gas separation selectivity was achieved with the PSf/P84 1:0.025 blended membrane for H₂/CH₄ (11.28, 58 % increase), H₂/CO₂ (6.25, 193 % increase), and H₂/N₂ (5.25, 35 % increase). The highest N₂/CH₄ selectivity (6.29, 253 % increase) was observed with the 1:0.10 composition. Regarding commercially relevant separations based on the 2008 Robeson curve, the PSf/P84 1:0.20 blend showed promise for H₂/CO₂ separation, while the 1:0.05 and 1:0.10 blends were suitable for N₂/CH₄ separation.

An attempt has been made to conserve the nutrition of butterfly pea by modifying the production process. In this paper, butterfly pea syrup was prepared through ultrasound assisted extraction (UAE) of butterfly pea flower using water at ultrasound frequency of 40kHz and initial temperature of 50 °C for 30 min. Extraction was modified by addition of sugar and citric acid. Before separation of extract, butterfly pea mixture was adjusted to contain 181,25 g sugar and 2.875 g citric acid per L water. The extract was then concentrated by vacuum evaporation at 50 °C for 2–6 h. The concentrated extracts were stored at 6 °C and 30 °C for 4 weeks. Each experiment was run triplicate and the effect of each treatment on the anthocyanin concentration was measured using UV–Vis Spectrophotometer. Results indicated that presence of citric acid and sugar during extraction affect extraction and shelf life of butterfly pea extract. The presence of citric acid and sugar in anthocyanin extracts also prolongs their shelf life.

Methylene Blue (MB) generates colored effluents that are difficult to treat. Solid Scale Waste (SSW) was studied as a catalyst in a Heterogeneous Fenton process for MB removal. The SSW was identified as a non-porous material with 97.5 % iron oxides. For the oxidative process, the exposure to light, amount of catalyst, and H₂O₂ dose were tested. The best conditions to enhance MB removal were 0.01g of catalyst, 0.035 mL of H₂O₂, and light; under these conditions, a removal percentage of 97.41 % was achieved. The kinetics results showed a pseudo-first-order reaction and an Activation Energy of 81.92 kJ/mol.

The study explored the treatment of different wastewater by producing microelectronic components. It proposed using aerobic biological treatment for the first effluent containing tetramethyl ammonium hydroxide and chemical-physical processes for the other two streams having fluorides, phosphates, nitrates and acetic acid. The novel integrated process significantly reduced environmental impacts by an average of 50 % compared to current disposal methods. The economic analysis indicates a 30 % reduction in treatment costs for the first effluent and lesser reductions for the other two effluents. The study revealed that treating all three effluents in an integrated manner is cost-effective, reducing investment and operating costs.

In the current work, new nanocomposite adsorbers of Cu-doped zeolitic imidazole framework (Cu-doped-ZIF-8) were constructed via in-suit assembled in the presence of both Zn and Cu ions, and analyzed using different techniques. The adsorptive efficiency of Cu-doped-ZIF-8 adsorber has been assessed toward Malachite Green (MG) dye removal. Compared with undoped-ZIF-8, adsorption uptake of Cu-doped ZIF-8 was enhanced 1.8 times, reaching 219 mg/g under constant conditions (solution pH = 6.8, initial MG concentration 30 mg/L, adsorber dose 0.5 g/L, and adsorption time 90 min). The boosted adsorption efficiency was owing to the effective π-complications originated between Cu nods and the MG dye molecules. According to the kinetic and adsorption-isotherm analyses, the Pseudo-first-order and Langmuir equations were matched well with the experimental adsorption process, suggesting that the chemisorption was controlled, and the Cu-doped-ZIF-8 sample displayed a uniform surface towards MG dye adsorption process. Furthermore, the stability of Cu-doped-ZIF-8 was tested, in which the MG adsorption capacity decreased only to 213 mg/g for after five adsorption cycles.

This paper reviews a study on processing titanomagnetites using low-temperature treatment and magnetic separation. Using a reduction agent (15 %), chloride additives (15 %), and calcium fluoride (5 %) in low-temperature treatment reduced titanium magnetite iron content. This process extracted iron from titanium precisely and thoroughly. The best low-temperature treatment time and temperature were 60 minutes and 1200 °C. Magnetic separation with 0.2 T magnetic field intensity yielded 75.5 % magnetic fraction. Titanomagnetites treated at low temperatures had 50.9 % magnetic portion iron. Magnetic fraction iron extraction was 97.8 %. The yield of 24.5 % was achieved while the non-magnetic concentrate's titanium dioxide content grew to 65 %.