Cost-effective and simple biodiesel production process from waste cooking oil using a rotating tube reactor: Kinetic study and techno-economic analysis

This study presents an efficient method for biodiesel production using a rotating tube reactor (RTR). The continuous production process from various feedstocks was simulated based on experimental data and kinetic modeling, and further evaluated to assess its economic feasibility. NaOH catalyzed transesterification of waste cooking oil (WCO) in the RTR was aligned in the pseudo-first order of WCO with an activation energy of 27.81 kJ/mol and pre-exponential factor of 3.76 × 103 min−1 (R2 = 0.9996). The continuous RTR can reduce FFA from 6 to 1.89 wt% via esterification of WCO. Turbulent Taylor vortex flow regime indicated that transesterification of WCO in the RTR required higher mixing intensity to achieve a high biodiesel yield of 89.72 % within 11.23 min. The RTR approach offers a comparable total capital investment to existing intensified methods while reducing operating costs, underscoring its potential for cost-effective biodiesel production. The economic evaluation indicated that biodiesel from high-FFA content WCO was more favorable, with a short payout period of only 3.1 years, a high net present value of 34.8 million USD, and an internal rate of return of 82.6 %. The RTR proves to be a viable, simple, and flexible solution for biodiesel production from various feedstocks

Atmospheric Nitrogen Plasma-Induced for Embedding NH2@Cubic-Bicontinuous Mesoporous Silica as Uranium (VI) Adsorbent Candidate in Seawater

This work aims to achieve interesting progress in uranium extraction by introducing a promising strategy that utilizes atmospheric nitrogen plasma-induced amine modification of CBC (Cubic Bi-continuous) material, providing a compelling pathway to enhance CBC's adsorption properties specifically for uranium harvesting. CBCs mesoporous silica samples were prepared by mixing the Pluronic F-127 as a template and TEOS (Tetraethyl Orthosilicate) as silica sources in the sol-gel process under acidic conditions. The obtained CBCs were treated using nitrogen plasma at room temperature (RT) under atmospheric pressure in a customized-borosilicate plasma reactor. Subsequently, the treated CBSs were grafted with amine groups. The final samples were characterized using SAXS (Small Angle Synchrotron X-ray Scattering) to determine the phase and structure, SEM-EDS (Scanning Electron Microscopy-Energy Dispersive Spectroscopy) analysis to quantify the presence of silica, oxygen, and embedded nitrogen, and Specific Surface Area (SSA) Analyzer using Brunauer-Emmett-Teller (BET) method to determine the specific surface area and pore size distribution. The SAXS profiles indicate that the obtained samples can be classified as CBCs Im3m mesoporous silica. The presence of silica, oxygen, and nitrogen was verified through SEM-EDS analysis, with approximate compositions of 36-37 %, 51-62 %, and 0.7-1.0 %, respectively. The use of SSA analysis further supported the findings, confirming the typical adsorption isotherm IV model. The specific surface areas were measured to be 371 m2/g for pure CBC, 573 m2/g for P1-CBC, and 607 m2/g for P2-CBC. The pore size distribution analysis revealed mesoporous characteristics within the material, with pore sizes ranging from 4 to 6.5 nm. On a batch laboratory scale, the material achieved the highest adsorption capacity of 15.68 mg-U(VI)/g-NH2@P1-CBC from natural seawater after 1 hour of contact time

Fluorometric Paper-Based, Loop-Mediated Isothermal Amplification Devices for Quantitative Point-of-Care Detection of Methicillin-Resistant Staphylococcus aureus (MRSA).

Loop-mediated isothermal amplification (LAMP) has been widely used to detect many infectious diseases. However, minor inconveniences during the steps of adding reaction ingredients and lack of simple color results hinder point-of-care detection. We therefore invented a fluorometric paper-based LAMP by incorporating LAMP reagents, including a biotinylated primer, onto a cellulose membrane paper, with a simple DNA fluorescent dye incubation that demonstrated rapid and accurate results parallel to quantitative polymerase chain reaction (qPCR) methods. This technology allows for instant paper strip detection of methicillin-resistant Staphylococcus aureus (MRSA) in the laboratory and clinical samples. MRSA represents a major public health problem as it can cause infections in different parts of the human body and yet is resistant to commonly used antibiotics. In this study, we optimized LAMP reaction ingredients and incubation conditions following a central composite design (CCD) that yielded the shortest reaction time with high sensitivity. These CCD components and conditions were used to construct the paper-based LAMP reaction by immobilizing the biotinylated primer and the rest of the LAMP reagents to produce the ready-to-use MRSA diagnostic device. Our paper-based LAMP device could detect as low as 10 ag (equivalent to 1 copy) of the MRSA gene mecA within 36-43 min, was evaluated using both laboratory (individual cultures of MRSA and non-MRSA bacteria) and clinical blood samples to be 100% specific and sensitive compared to qPCR results, and had 35 day stability under 25 °C storage. Furthermore, the color readout allows for quantitation of MRSA copies. Hence, this device is applicable for point-of-care MRSA detection