Search

This research investigates the synthesis and application of Losod-zeolite (LOS-Z), a crystalline hydrated sodium aluminosilicate (Na12Al12Si12O48.xH2O) as a potential photocatalyst for dye degradation and H2 production from dye-degraded water. The photocatalytic properties are enhanced by impregnating molybdenum (Mo) into LOS-Z (Mo@LOS-Z). XRD, FTIR, SEM, EDX, and elemental mapping were used to study the physicochemical properties of synthesized materials while UV–vis and PL were employed to explore the optoelectronic properties. The photocatalytic activities for dye degradation and H2 production were evaluated using methylene blue (MB) under visible light irradiation. An enhancement in the efficiency of dye degradation (56%–82%) and H2 production rate was demonstrated due to the competitive photocatalytic performance of 10% Mo@LOS-Z compared to the pristine LOS-Z and CFA-BFA blend. It exhibited 2.5 times higher (∼1200 μmol g−1h−1) H2 production than the LOS-Z (∼480 μmol g−1h−1) due to the synergistic effects of narrowed band gap and recombination rate. This study could pave the way forward into the synthesis of waste-derived photocatalysts for efficient dye degradation and H2 production.

Flexible capacitive energy storage applications require polymer nanocomposites with high dielectric properties, which can be accomplished by addition of inorganic nanofillers to the polymer matrix. Low-density polyethylene (LDPE), known for its good dielectric characteristics and wide use in electrical insulation have been investigated for the desired applications. However, the improvement of its breakdown strength still continues with the use of various nanomaterials employed as nanofillers. In this study, a waste-derived material known as biomass fly ash (BFA) as a nanofiller to improve the dielectric properties of LDPE has been explored. BFA exhibits versatility in its composition with various metal oxides, making it an attractive choice as a nanofiller. The BFA-LDPE sheets were prepared using a conventional solvent mixing and subsequent hot-pressing process, incorporating BFA loadings ranging from 1 % to 4 wt%. The effects of different BFA loadings were carefully examined, and the synthesized nanocomposites were extensively characterized using various characterization methods, such as XRD, SEM, FTIR, TGA and dielectric constant measurements, to investigate the crystallographic properties, morphology, chemical composition, and thermal stability. Among all the nanocomposites, 4 wt%BFA-LDPE exhibited the highest dielectric constant, with a value of 11.58, compared to simple LDPE that had a dielectric constant of 8.33. This improvement is ascribed to the synergistic effects of different inorganic metal oxides (SiO2, MgO, and Fe2O3) present in BFA. The results showed a significant enhancement in dielectric properties, indicating that the waste-derived BFA can be purposefully applied as an effective nanofiller in the LDPE-based composites with even less than 4% loading for electrical insulating applications in future studies.

In this era, renewable energy technologies are suitable to meet the challenges of fossil fuel depletion and global warming. Thus, hydrogen is gaining attention as an alternative clean energy carrier that can be produced from various methods, one of them is the iodine-sulfur (I–S) cycle which is a thermochemical process. The I–S cycle requires a material that can withstand an extremely corrosive environment at high temperatures. Immersion tests were conducted on bare superalloy Hastelloy X (HX), MoSi2, and SiC–MoSi2 coated HX, deposited in physical vapor deposition (PVD) to evaluate their corrosion resistance. Bare HX exhibited a high corrosion rate of 208.1 mm yr−1 when exposed to 98 wt% sulfuric acid at 300 °C. In contrast, HX with MoSi2 coating showed a much lower corrosion rate of 23.5 mm yr−1, and HX with SiC–MoSi2 coating demonstrated the lowest corrosion rate at 6.5 mm yr−1 under the same conditions. The coated samples were analyzed via FESEM before and after corrosion testing. The FESEM images reveal the formation of coalescent particles on the surface of the coating. The elemental analysis illustrates an increased concentration of silicon and oxygen in the corroded samples. Elemental mapping of these samples show a uniform distribution of elements over the sample. These findings contribute not only to materials science understanding but also to practical applications in hydrogen production via the I–S cycle, where corrosion-resistant materials are critical.

In this work, the biomass fly ash (BFA) supported Ni/La2O3 catalyst was synthesized for the first time to produce syngas, a mixture of CO and H2 via the partial oxidation of methane (POM). The BFA support was modified using laboratory synthesized Ni/La2O3 through the wetness impregnation technique. The Ni/La2O3-BFA catalyst was characterized by several techniques to investigate its suitability for the POM reaction. The characterization results showed that the crystalline structure, better metal support interaction and enhanced thermal stability of Ni/La2O3-BFA make it suitable for the POM. The synthesized Ni/La2O3-BFA catalyst remained stable for 30 h on stream during POM at 850 °C. The addition of La2O3 promoter and active metal Ni to the BFA improved the CH4 conversion from 55% to 85% and enhanced the H2/CO ratio from 1.4 to 2.0 while maintaining a reactants stoichiometric ratio of (CH4:O2 = 2:1). The study of spent catalyst by using various techniques confirmed that the stable catalyst exhibited coke resistance in the POM even after 30 h time on stream. Thus, the performance of BFA supported Ni/La2O3 catalyst shows more potential for catalytic applications due to its suitable physiochemical properties as it is a combination of multiple oxides that synergistically participate in the reaction steps and increases syngas production. It also provides low-cost, abundant, greener, and waste based alternative to expensive metal oxide as supports for catalytic applications.

The purpose of this study is to investigate the potential use of solar energy within an oil refinery to reduce its fossil fuel consumption and greenhouse gas emissions. A validated ASPEN HYSYS model was used to investigate the products produced from heavy crude oil in the refinery. Using TRNSYS software, the proposed Parabolic Trough Collector (PTC)-based solar heating system paired with the boiler is modelled. Sensible thermal energy storage (TES) system is integrated into the refinery's process heating to handle the intermittent nature of solar energy. It was discovered that 463 m2 of the PTC area coupled with a 15000-L TES tank can result in a maximum life cycle cost savings of 21.046 thousand USD for an annual heat supply of 116,944 MWh to generate steam at a temperature of 200–220 °C. In the proposed hybrid heating system, the yearly solar fraction is determined to be 26.99% and the payback period is 8.77 years with the average solar irradiance of 900 W/m2. In addition, the system can yearly reduce greenhouse gas (GHG) emissions by about 34.045 tonnes of CO2 equivalents.

This study is designed to examine the feasibility of the solar water heating (SWH) system for sustainable tourism in Gilgit-Baltistan (GB) of Pakistan and a tourist resort is taken as a base case. Hot water demand, solar irradiance and economic feasibility are the key parameters considered to investigate the potential of SWH systems using simulation tool T*SOL. Three different types of solar collectors were investigated, based on solar fraction, maximum collector temperature and overall system efficiency. Among these collectors, the evacuated tube collectors (ETC) show high solar fraction, efficiency and CO2 emissions saved as compared to flat plate collectors (FPC) and unglazed collectors (UnGC), for both locations. The ETC shows 75 % solar fraction, 40 % efficiency, and 676 kg CO2 emission saved and payback period of is recorded 6.6 years for Gilgit. While for Skardu, 84 % solar fraction, 36 % efficiency, 756 kg CO2 emissions avoided and payback period of 4.6 years is analysed. Sensitivity analysis based on design parameters such as collector area, tilt angle and tank volume is performed to highlight the important design considerations. Based on the techno-economic analysis, it is concluded that ETC is the most feasible SWH system for the northern regions of Pakistan.

In this research, a dielectric barrier discharge (DBD) reactor is used to study the cracking of the toluene into C1–C6 hydrocarbons. The combined effect of parameters such as temperature (20–400 °C) and plasma power (10–40 W) was investigated to evaluate the DBD reactor performance. The main gaseous products from the decomposition of toluene include lower hydrocarbon (C1–C6). The cracking of toluene increases with power at all temperatures (20–400 °C). On the otherhand, it decreases from 92.8 to 73.1% at 10 W, 97.2 to 80.5% at 20, 97.5 to 86.5% at 30 W, and 98.4 to 93.7% at 40 W with raising the temperature from 20 to 400 °C. Nonetheless, as the temperature and plasma input power increase, the methane yield increases. At 40 W, the maximum methane yield was 5.1%. At 10 and 20 W, the selectivity to C2 increases as the temperature rises up to 400 °C. At 30 and 40 W, it began to drop after 300 °C due to the formation of methane and the yield of methane increases significantly beyond this temperature.

Brick kiln sector in South Asia contributes to nearly quarter of the global bricks production. Coal is the primary fuel used by this industry and its inefficient combustion process results in harmful pollutants contributing to deteriorating air quality, health problems in local communities, and greenhouse gas emissions. The aim of this study is to investigate the impact of cleaner technologies and adoption pathways to achieve environment-friendly and energy-efficient production of bricks in Pakistan during 2019–2050. The study incorporates various timelines for (Zig-Zag Kilns) ZZKs and Vertical Shaft Brick Kilns (VSBKs) adoption, and the phasing out of conventional, Fixed Chimney Bull’s Trench Kiln (FCBTKs). Low Emissions Analysis Platform (LEAP) based numerical calculations are performed to simulate brick production from 2019–2050 for seven different scenarios incorporating an assimilated technology mix of FCBTKs, ZZKs, and VSBKs. Emissions of carbon dioxide, carbon monoxide, black carbon, methane, non-methane volatile organic compounds, particulate matter, sulfur oxides and nitrogen oxides are considered in this study. The swiftness of energy demand, and emissions reductions are greatly impacted by the elimination of the conventional FCBTKs. By adopting clearner brick manufacturing, 365.5 million tons (21.8%) of GHG emissions reduction can be achieved. The annual social cost of using FCBTKs increases from 1.02 billion $ in 2019 to 1.88 billion $ in 2050. Cumulative fuel saving potential of retrofitting to ZZKs is 157 million tons (17.7%) and it offers nearly 0.92 billion $ (51%) savings in annual social cost for year 2050. Our study finds that early adoption of ZZKs would benefit more than delayed adoption of VSBKs. However, transition to ZZK/ VSBK alone would not be sufficient to achieve net-zero carbon emissions. Carbon neutral fuels such as biomass and refuse-derived fuel (RDF) appear as an attractive option for deep decarbonization of this sector.

Perovskite solar cells (PSCs) are rapidly emerging as efficient solar cells due to the efficient photovoltaic and physiochemical properties. Ideally, the absorber layer in PSCs is sandwiched between highly conductive electron transport layer (ETL) and highly stable hole transport layer (HTL). The interfaces between these layers highly affect the performance of PSCs. In this study Magnesium (Mg) doped TiO2 based ETL is systematically investigated to enhance the optical and morphological properties of the layer and the interface. It was observed that with Mg doping in mesoporous TiO2, morphology of TiO2 based ETL film was significantly improved thereby providing an interface for the growth of absorber layer. Optoelectronic studies suggested that band gap was effectively reduced with the addition of Mg and absorption range was also enhanced. Electrical analysis yielded, Mg doped TiO2 based ETL showed enhanced conduction and better sheet carrier mobility as compared to undoped films. Thermal studies indicate fabrication of a thermally stable ETL material for PSCs. Moreover, Current density-Voltage (J-V) measurements indicated more than two-fold increase in photovoltaic efficiency of 3 wt% Mg.