Development of solar still for water purification and its performance analysis

Desalination process through solar still has been found to be the most economical technique, as it makes use of a free source of energy. The main drawback of this equipment is its low productivity. Thus, numerous enhancements have been developed throughout the years to improve its performance. In this study, the solar still underwent improvement using three simple enhancers, namely, aspirator, magnifying glasses (lenses), and heat transfer agent (HTA). Four sets of experiment were carried out to compare the performance of the solar still with different set-ups: Set 1 (aspirator), Set 2 (aspirator+ HTA), Set 3 (aspirator+ lenses) and Set 4 (aspirator +HTA +lenses). The experiment using the set with the highest efficiency was repeated with different feed which is seawater (Set 5). The highest collected evaporated volume was achieved by Set 4 at a total of 4.86 L while Set 1, Set 2 and Set 3 had a total of 0.68 L, 1.45 L and 3.43 L, respectively. The evaporation rates were proportional to the maximum instantaneous efficiency as Set 4 recorded the highest thermal efficiency of 70%, followed by Set 3, Set 2 and Set 1 with the percentage of efficiency at 51%, 42%, and 31%, respectively. For Set 5, the total collected evaporated volume is 4.23 L. Therefore, it can be concluded that although a slight improvement was observed, the effect of introducing the HTA was not significant. Nevertheless, if the HTA were combined with lenses in a vacuum solar still, the effect would be enormously significant. The water comparison analysis shows a very significant value between Set 4 and Set 5 at the initial state but small distinction at the final state. The results show that the performance of solar still increase significantly with the presence of lenses and HT A together. However, when the solar still is applied with HTA alone, only slight improvement is achieved compare to the application of lenses alone

Effect of methacrylic acid monomer on the reverse salt diffusion in chemical grafted forward osmosis membrane

Reverse salt diffusion (RSD) is a common issue in forward osmosis (FO) membrane normally contribute to substantial fouling and lead to a lower water flux. Commercial nanofiltration (NF) membrane surface was grafted using chemical grafting for controlling this RSD issue. Different concentrations of 0.3, 0.6, and 1.0 M of methacrylic acid (MA) were selected as main monomer while potassium persulfate and sodium metabisulfite (K2S2O8/Na2S2O5) with concentration of 0.01 M as pair of initiators were used for the grafting modification. Then the grafted membrane was evaluated in term water flux (Jw) and RSD using 1 M sodium chloride (NaCl) as draw solution. The result shows that, the highest Jw (0.7534 L/m2.h) and the lowest RSD (4.272 g/m2.h) both were recorded at the grafting of 30 min with 1.0 M concentration of MA. Both performance increase with the increasing in the MA concentration and grafting time. Therefore, modification of the commercial NF membrane using chemical grafting can therefore be used as an alternative technique for enhancing the performance of commercial membrane in the application of FO

Water flux prediction of UV-photografted nanofiltration membrane for forward osmosis application

In the application of forward osmosis, commercial nanofiltration (NF) membrane was modified via ultraviolet(UV)-photografting technique at different grafting parameters; monomer concentration (acrylic acid) and grafting time. However, the performance of the modified membrane measured at the osmotic pressure of 1M NaCl as draw solution limits their applications. In this research, the mathematical modelling was applied to predict the water flux at different osmotic pressure. The mathematical modelling indicated that the generated water flux follows the osmotic pressure but strictly affected by the grafting parameters. The result shows that at grafting time of 3min, the monomer concentration of 15 g/L generates the highest water flux followed by the membrane modified at the monomer concentration of 30 g/L. High water flux was attributed to the presence of strongly hydrophilic groups at new carboxyl layers leading to improved membrane properties. The approach of theoretical modelling on the membrane that is reported in this work allows estimating the water flux at different grafting parameter

Effect of methacrylic acid monomer on UV-grafted polyethersulfone forward osmosis membrane

UV irradiation is one of the procedures that has been considered for membrane surface graft polymerization. It is commonly utilized for enhancing the wettability of polyethersulfone (PES) membranes. In this research study, the monomer methacrylic acid (MAA) was used for the UV grafting process of a commercial NF2 PES membrane for the preparation of a forward osmosis (FO) membrane. Three different monomer concentrations and three different UV irradiation times were considered. The intrinsic characteristics of both the surface-modified and pristine membranes were determined via a non-pressurized test method. Compared to the NF2 PES, the surface of the modified membranes was rendered more hydrophilic, as the measured water contact angle was reduced considerably from 65° to 32–58°. The membrane surface modification was also confirmed by the data collected from other techniques, such as atomic force microscopy (AFM), field emission-scanning electron microscope (FESEM) and Fourier-transform infrared spectroscopy–attenuated total reflectance (FTIR–ATR). Additionally, the modified membranes exhibited a greater water permeate flux (Jw) compared to the NF2 PES membrane. In this study, the water permeability (A), solute permeability (B) and structural parameter (S) were determined via a two-stage FO non-pressurized test method, changing the membrane orientation. Compared to the FO pressurized test, smaller S values were obtained with significantly high A and B values for the two non-pressurized tests. The adopted method in the current study is more adequate for determining the intrinsic characteristics of FO membranes

Determination of Phytochemical in Extracted Punica Granatum Peels and its Efficacy of Healing Burn Injuries

Natural plants have been used as a traditional medicine all over the world. One of these natural plants is pomegranate (punica granatum). This study aimed to determine the phytochemicals from Pomegranate peels that can heal burn wounds by extracting the peels. Additionally, this study is investigating the efficiency of Pomegranate (Punica granatum) in curing the burn wounds compare to the commercial ointment. Extracting the pomegranate start with drying the peels under room temperature, followed by drying in the oven for 48 hours with the temperature of 50oC, then grinding them. However, after the preparation of the ointment from the peels fine powder, four different samples of rats were burnt and treated. The result of the extract and the analysis showed that pomegranate is reach by an active constituent such as Saponin, Glycosides, Steroids and Terpenoid which play the main role in healing the burn wounds. This claimed is supported by the result of the treatment observations of the rats' samples which proof that the efficiency of using pomegranate ointment in curing the wounds is higher and faster than the commercial ointment. As conclusion the objective of this study has been achieved, and positive result has been obtained

Solar Still: Water for the Future

Being an abundant natural resource that covers three quarters of the earth’s surface, water still a major issue, as less than 1% of fresh water is actually within human reach. Solar energy, most recommended renewable energy source is widely used in desalination fields. Solar distillation, particularly solar still is expected to solve this fresh water production problem without causing any fossil energy depletion, hydrocarbon ollution and environmental degradation. However, the efficiency of the solar still is debatable. As the main reason of low productivity in a solar still is the low heat transfer inside the unit itself therefore, a thoroughly modification on solar still design is presented based on the scope of increasing the heat transfer process inside the unit. Significantly, ntroducing optical controlling techniques together with focused sunlight receiver and having the process to operate under low pressure have speed up the rate of production within 10 hours of day light. However, the presence of focused sunlight receiver is not seem to improve the production of the solar still yet an increase value is recorded