A key review of non-industrial greywater heat harnessing

The ever-growing concerns about making buildings more energy efficient and increasing the share of renewable energy used in them, has led to the development of ultra-low carbon buildings or passive houses. However, a huge potential still exists to lower the hot water energy demand, especially by harnessing heat from waste water exiting these buildings. Reusing this heat makes buildings more energy-efficient and this source is considered as a third-generation renewable energy technology, both factors conforming to energy policies throughout the world. Based on several theoretical and experimental studies, the potential to harness non-industrial waste water is quite high. As an estimate about 3.5 kWh of energy, per person per day could be harnessed and used directly, in many applications. A promising example of such an application, are low temperature fourth generation District Heating grids, with decentralized sources of heat. At the moment, heat exchangers and heat pumps are the only viable options to harness non-industrial waste heat. Both are used at different scales and levels of the waste-water treatment hierarchical pyramid. Apart from several unfavourable characteristics of these technologies, the associated exergetic efficiencies are low, in the range of 20–50%, even when cascaded combinations of both are used. To tackle these shortcomings, several promising trends and technologies are in the pipeline, to scavenge this small-scale source of heat to a large-scale benefit

In situ immobilization of CuO on SiO\u3csub\u3e2\u3c/sub\u3e/graphite matrix, modified with benzimidazolium-1-acatate ionic liquid: Application as catechol sensor

© 2017 Carbon ceramic material (SiO2/C) was prepared using the sol-gel technique. Copper oxide was in situ synthesized on the pores of the matrix, to ensure homogenous distribution of the electroactive species in the matrix pores. To enhance the conductivity of material, the SiO2/C/CuO was modified with benzimidazolium-1-acetate ionic liquid. The surface area (SBET 432.56 m2/g) and pore volume (0.90 cm3/g) of the material were calculated from BET analysis. SEM images showed compactness of materials, having no phase segregation within the magnification used. The structure of ionic liquid was confirmed using NMR and FTIR analysis. The electrodes as a pressed disk fabricated from SiO2/C, SiO2/C/CuO, and SiO2/C/CuO/IL materials were tested as an electrochemical sensor for catechol determination. Electrochemical impedance spectroscopy has revealed that the SiO2/C/CuO/IL-based sensor assists the charge transfer owing to electron rich density, resonance, and conductance of ionic liquid structural moiety. SiO2/C/CuO/IL electrode exhibits excellent sensitivity, linear response range and low limit of detection (LOD) of 712 μA μmol− 1 dm3 cm− 2, 0.2 mM–10 mM and 0.7 × 10− 8 mol L− 1, respectively. The sensor was also tested for the determination of catechol in real samples and gives very good results for its determination

Surface engineered mesoporous silica carriers for the controlled delivery of anticancer drug 5-fluorouracil: Computational approach for the drug-carrier interactions using density functional theory

Introduction: Drug delivery systems are the topmost priority to increase drug safety and efficacy. In this study, hybrid porous silicates SBA-15 and its derivatives SBA@N and SBA@3N were synthesized and loaded with an anticancer drug, 5-fluorouracil. The drug release was studied in a simulated physiological environment.Method: These materials were characterized for their textural and physio-chemical properties by scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), small-angle X-ray diffraction (SAX), and nitrogen adsorption/desorption techniques. The surface electrostatics of the materials was measured by zeta potential.Results: The drug loading efficiency of the prepared hybrid materials was about 10%. In vitro drug release profiles were obtained in simulated fluids. Slow drug release kinetics was observed for SBA@3N, which released 7.5% of the entrapped drug in simulated intestinal fluid (SIF, pH 7.2) and 33% in simulated body fluid (SBF, pH 7.2) for 72 h. The material SBA@N presented an initial burst release of 13% in simulated intestinal fluid and 32.6% in simulated gastric fluid (SGF, pH 1.2), while about 70% of the drug was released within the next 72 h. Density functional theory (DFT) calculations have also supported the slow drug release from the SBA@3N material. The release mechanism of the drug from the prepared carriers was studied by first-order, second-order, Korsmeyer–Peppas, Hixson–Crowell, and Higuchi kinetic models. The drug release from these carriers follows Fickian diffusion and zero-order kinetics in SGF and SBF, whereas first-order, non-Fickian diffusion, and case-II transport were observed in SIF.Discussion: Based on these findings, the proposed synthesized hybrid materials may be suggested as a potential drug delivery system for anti-cancer drugs such as 5-fluorouracil

Phase change materials embedded with tuned porous media to alleviate overcharging problem of cascaded latent heat storage system for building heating

Cascaded latent heat storage (CLHS) has been used for building heating to balance renewable energy supply–demand mismatch and improve thermodynamic performance. In a cascaded latent heat storage system, the asynchronous phase transformation process of phase change materials (PCMs) at each stage leads to an overcharging problem, which reduces the heat storage rate and increases the heat loss. This study proposes a new solution to overcome this problem by embedding porous media with tuned porosity arrangement in cascaded PCMs. A 3-D transient numerical model is established to investigate the effects of tuned porosity arrangement on the charging and discharging performance of a CLHS system. The results show that this solution improves the synchronization of the phase transformation process of the PCMs to increase the latent heat storage rate and eventually the total heat storage rate of the system. Compared with a uniform porosity arrangement, the overcharging time and the overcharging time ratio of the system with tuned porosity arrangement decrease up to 89.66% and 91.93%, while the mean total heat storage rate increases by 73.21% during the melting process. In addition, the tuned porosity arrange�ment is beneficial to prolong heat supply time and increase the accumulated discharged heat. In all cases, the optimal tuned porosity arrangement is 0.90–0.95–0.97. The CLHS system with tuned porosity arrangement has the general good performance under different charging and discharging conditions. The proposed solution provides guidance for performance enhancement and optimization of CLHS systems for building heating