Plexiglas: from synthetic glass to cationic exchanging resin
Plexiglas is a macromolecule (poly-methyl-methacrylate) obtained by polymerization of the Methyl Methacrylate. Cation exchanging resins have acidic groups such as COOH (carboxyl) and SO3H (sulfonic) which fix metallic cations dissolved in water releasing an equivalent of protons through the following reaction: 2 RCOOH + Me2+ (RCOO)2Me + 2 H+ Regeneration is made treating the exhausted resin with diluted hydrochloric acid (HCl) which moves the equilibrium to the left. The aim of our research is to re-use the discarded Plexiglas by transforming it into a cationic exchanging resin. Alkaline hydrolysis transforms the COOCH3 group into COO– group; the obtained group is then transformed into COOH group by means of a treatment with HCl. After the alkaline hydrolysis spectra of the solid show the characteristic band of the asymmetric stretching of the COO– (1610-1550) at 1567 (1st experiment) and at 1555 (2nd experiment). Instead after the acidic treatment the spectra of the solid show that this band has disappeared. On the contrary the characteristic band of the OH stretching of the COOH group (3300-2500) at 3228 (1st experiment) and at 3200 (2nd experiment) appears. The water hardness, due to Ca2+ and Mg2+ ions, is studied to verify the capability of the obtained resin to capture these cations. For this purpose, some mineral water is percolated through the micro-columns. There are three experimental evidences to validate the hypothesis: EDTA molecule (Ethylene Di-amino Tetra-Acetic acid, disodium salt) to estimate hardness is not required The pH of the percolated water through the column decreases from 8 of the mineral water without any treatment, to 6.3 after the treatment as expected The spectrum recorded in the visible range of the percolated mineral water through the column plus EBT (Eriochrome Black T) indicator is the same as the spectrum obtained using de-ionized water plus the same amount of EBT In conclusion, the study has provided evidence that it is possible to convert Plexiglas into cationic exchanging resin.
An Innovative Design of Enhanced-Performance Solar Panel Using Heat Pipe and Thermoelectric Generator
Solar energy is a main source of energy that is expected to play a vital role in fulfilling the future global demand of electricity. Design of advanced photovoltaic (PV) system with high electric conversion efficiency is the key for collecting solar energy. A major obstacle hindering useful PV utilization is the deterioration of solar cell efficiency with temperature. The present results of experimentation have shown that there occurs a reduction of approximately 33% in the solar panel efficiency as the operating temperature increases from 45 °C to 68 °C at 1000 W/m2. Therefore, an innovative design of enhanced-performance solar panel using micro flat heat pipe (HP) and thermoelectric generator (TEG) is proposed and experimentally investigated in the presented project. To operate HP and TEG at highest possible efficiency, the condensation section of HP is innovatively cooled by utilize the condensed water inside the evaporator of air conditioner (which is usually between 5-7 °C). Two different types of silicon panel are used in the study: monocrystalline solar panel and polycrystalline solar panel. The results showed that a reduction in average solar panel temperature up to 25% is obtained. In addition, produced power was increased by as much as 50% when solar panel was cooled by the heat pipe. Finally, the feasibility study and cost analysis of the proposed hybrid system are discussed in details and presented.