Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 15, Issue 3, 2022

Paraffin emulsion is a highly dispersed, thermodynamically unstable system. Emulsifiers play a key role in promoting emulsion formation and improving emulsion stability. However, a single emulsifier has limitations in maintaining emulsion stability, usually, it is necessary to compound more than two emulsifiers or add other additives to make the paraffin emulsion have better stability. Therefore, how to keep paraffin emulsion high dispersibility and stability for a long time are the problems that the majority of researchers have been concerned about. This paper expounded the instability mechanism of paraffin wax emulsion. The process of paraffin emulsion destabilization is the process of gradually reducing the free energy of the system and the interaction force between emulsion droplets determines the speed of emulsion destabilization. Sedimentation and stratification, flocculation, coalescence, and Ostwald Ripening were the main factors leading to paraffin instability; the prevention and improvement methods are proposed for the above four mechanisms. From the instability mechanism, the factors affecting the stability of paraffin emulsion mainly include the mechanical strength and film elasticity of the interface film, the interfacial charge or obstruction between the emulsion droplets, the appropriate system viscosity, and the uniform droplet size distribution will affect the stability of the paraffin emulsion. Through literature research, several methods to improve the stability of paraffin emulsion were summarized. Polar paraffin has good emulsifying properties, compounding with paraffin can not only reduce the amount of emulsifier but also enhance the stability of paraffin emulsion, adding thickeners can reduce the Brownian motion of droplets and improve the chemical and mechanical stability of wax emulsions, the addition of ionic surfactants can reduce the diffusion rate of the dispersed phase, the addition of inorganic salts can make the emulsion droplets generate strong repulsion when they are close to each other, and improve the stability of the emulsion, the addition of small molecular alcohols can improve the flexibility of the oil-water interface film properties, reduce the surface tension coefficient of the emulsion, and increase the stability of the paraffin emulsion. This paper can provide a theoretical reference for the research on the stability of paraffin emulsion.

Volatile organic compounds (VOCs) are a group of organic compounds such as aromatic, aliphatic and chlorinated hydrocarbons, etc. VOCs are emitted into the atmosphere during the production of adhesives, paints, printing materials, building materials, and their use. Although several removal approaches have been employed to remove VOCs, researchers have not stopped exploring new methods and materials for VOCs treatment. Graphene has recently attracted enormous attention for fundamental research and potential applications due to its large specific surface area, high mechanical strength and flexibility, and good chemical and thermal stability. Here we briefly describe the recent progress in graphene-based materials (GBMs) for applications in VOCs removal. GBMs have been exploited as novel materials in VOC adsorption, membrane separation, and photocatalysis. Although the issues need to be further studied, such as biocompatibility, toxicity, and production at low cost, GBMs are promising for VOC removal, which is the current trends and future perspectives of the field. This mini-review represents the potential of GBMs for VOC treatment.

Omnipresence of microplastics (<5mm) in our ecosystem has presented a worldwide concern for the future. This review aims to highlight the toxic effect of microplastic on marine organisms, identify the research gaps in the microplastic identification techniques (Fourier transform infrared spectroscopy, Raman spectroscopy, Pyrolysis- gas chromatography/mass spectroscopy, etc.) and remediation processes available (flocculation, membrane bioreactor, bioremediation, etc.) as well as throw light on the prospects to mitigate the microplastic pollution in the environment. The abundance of microplastics in the oceans and its subsequent ingestion causes false satiation leading to starvation, weakened immune system, reduced reproduction rate, and other toxic effects on marine organisms. Recent studies have also found the presence of microplastics in human bodies, without the true knowledge of its effects. Based on the reviewed literature, a combination of different analytical (identification) techniques is proven to be more useful in providing a detailed understanding of the microplastic sample in comparison to any one individual technique. Amongst all the available remediation techniques, bioremediation has shown the potency to be used as a sustainable, environment friendly, in-situ remediation process with engineered microbes/enzymes as the potential future of microplastic remediation.

Background: The fibers of date palm (DPFs) were used as a raw material to isolate cellulose nanofibers (CNFs) to assess their potential as reinforcements of composite materials in producing Bioplastic. The isolation of Nano cellulose (NCs) from DPF is still lacking, and the authors are not aware of any previous publication concerning the isolation of NCs from DPF. Objective: The date palm has huge potential in the application as a reinforcement agent to manufacture bio-nano composites and can be considered a renewable source of nanofibers with an etymology of agro-waste. Methods: High-purity cellulose nanofibers were isolated from DPFs through an environmentally friendly treatment that combined chemical (alkali & bleaching) and mechanical processes (ball milling). Results: A high yield of CNFs was successfully extracted, with 50% CNFs from overall DPFs. Scanning electron microscopy (SEM) results revealed the effects of isolation treatments on fiber morphology and showed long, loose nanofiber bundles with 8-100 nm diameter. FTIR results showed that noncellulosic components were effectively removed. X-ray diffraction analysis revealed the improved crystallinity of the processed fibers with a high crystalline index of 69.78%. Conclusion: TGA results showed an enhancement in the thermal properties of the nanofibers. The removal of hemicellulose and lignin increased the crystallinity of the fibers, and the extracted CNFs were used in the synthesis of Bioplastic by using glycerol as a plasticizer and corn starch as a matrix using the casting method. The feasibility study proved that NC production is feasible in Oman and successfully yielded cellulose nanofibers with potential in advanced applications. The availability of raw materials is sufficient to sustain the plan with a total capital investment of OMR 9,694,127, an operating cost of OMR 10,058,976, and a total annual net profit of OMR 2,235,445.926, which shows an ROI of 23%/year with a payback period of 4.34 years.

Background: This study aimed to optimize a process for removing Fe-Cu from wastewater using biodegradable adsorbents. Objective: The objective of the study is to remove copper ions from wastewater. The use of low-cost adsorbents was investigated as a replacement for the conventional methods of removing heavy metals from an aqueous solution. Methods: Removal of copper (II) from an aqueous solution by the adsorbent made from the jackfruit peels was investigated and analyzed with the help of UV-spectroscopy. The conventional treatment methods for heavy metal contamination include chemical precipitation, chemical oxidation, ion exchange, reverse osmosis, membrane separation, electrodialysis, and so on. These techniques are very costly, require energy in huge quantities, and generate toxic byproducts. On the other hand, adsorption has been investigated as a cost-effective method for removing heavy metals from wastewater. The equilibrium adsorption level was determined as a function of particle size, adsorbent doses, and variable concentration of metal ion solution. Adsorption isotherms of Cu (II) on adsorbents were selected and correlated with isotherm equations, including Langmuir and Freundlich models. Results: From the experiment, the maximum percentage of copper removed was 84.30%, and the maximum adsorption capacity was 11.24 mg/g for particle size of 0.212 mm, 30.98 mg/g for 1 gram of adsorbent dose, and 5.23 mg/g for 300 ppm of concentration of metal ion solution. Conclusion: The adsorbent made from the jackfruit peels is more effective for removing copper from aqueous solutions emitted from the industrial wastes. It can prove to be the best alternative to the conventional method.

Background: Energy is a fundamental requirement in economic growth and is directly related to almost all aspects of global development. The global energy demand is increasing daily due to the expanding economy, industrialization, and population growth. Countries have adopted the trend of renewable energy over non-renewable energy due to the sustainability of renewable energy sources. Bloom energy server is a renewable energy source that utilizes solid oxide fuel cell (SOFC) technology to convert fuel into electricity through an electrochemical reaction with high efficiency and without combustion. Oman, however, still relies on non-renewable energy sources, namely oil and gas. Countries continuously apply the most efficient and cost-effective energy sources with the other different energy sources available. Objective: This paper aims to investigate the different available energy sources, both renewable and non-renewable and compare them and the bloom energy server and make conclusions that Oman can adopt. Methods: The methodology used was a comprehensive literature search of the Google Scholar database, ProQuest database and Google search. The energy sources investigated are SOFC, solar power, wind energy, hydropower, crude oil energy, coal energy and natural gas. The variant energy sources were compared based on the following parameters: capacity capital cost, reliability and availability, sustainability, lifetime, environmental concerns, efficiency, and long-term cost-effectiveness. Results: Results showed that renewable energy sources are superior to non-renewable energy sources. Of the renewable sources, SOFC was the most reliable, hydropower the most efficient with the longest lifetime, and solar and wind energy provided a long-term, cost-effective energy option. Conclusion: In conclusion, perhaps bloom energy servers are not the best option for Oman, but the adoption of renewable energy sources is strongly urged.