SEMI-BATCH OPERATED CONSTRUCTED WETLANDS PLANTED WITH PHRAGMITES AUSTRALIS FOR TREATMENT OF DYEING WASTEWATER

The objective of present study is to evaluate the using of constructed wetland under semi-batch operation for the treatment of azo dye Acid Orange 7 (AO7) containing wastewater. The emergent plant selected in our study was Phragmites australis. Toxic signs were observed at the Phragmites australis after the addition of AO7 into the wetland reactors but it can adapt to the wastewater as shown in the increase of stem as the operation continue. Our result shows that the artificial aeration and the presence of Phragmites australis had a significant impact on the removal of organic matters, AO7, aromatic amines and NH4-N. The COD removal efficiency in the aerated and non-aerated wetland reactors was 95 and 62%, respectively. The NH4-N removal efficiency in the aerated wetland reactor (86%) was significantly higher than the non-aerated wetland reactor (14 %). All wetland reactors show high removal efficiency of AO7 (> 94%) but only the aerated wetland reactor perform better in the removal of aromatic amines

Enhanced photodegradation of phenol by ZnO nanoparticles synthesized through sol-gel method

Zinc oxide (ZnO) utilization in advanced oxidation process (AOP) via solar-photocatalytic process was a promising method for alternative treating wastewater containing phenol. The ZnO photocatalyst semiconductor was synthesized by sol-gel method. The morphology of the ZnO nanostructures was observed by using scanning electron microscope (SEM) and the crystallite phase of the ZnO was confirmed by x-ray diffraction (XRD). The objective of this study was to synthesis ZnO nanoparticles through a sol-gel method for application as a photocatalyst in the photodegradation of phenol under solar light irradiation. The photodegradation rate of phenol increased with the increasing of ZnO loading from 0.2 until 1.0 g. Only 2 h were required for synthesized ZnO to fully degrade the phenol. The synthesized ZnO are capable to totally degrade high initial concentration up until 45 mg L-1 within 6 h of reaction time. The photodegradation of phenol by ZnO are most favoured under the acidic condition (pH3) where the 100% removal achieved after 2 h of reaction. The mineralization of phenol was monitored through chemical oxygen demand (COD) reduction and 92.6% or removal was achieved. This study distinctly utilized natural sunlight as the sole sources of irradiation which safe, inexpensive; to initiate the photocatalyst for degradation of phenol

Decolorization and mineralization of batik wastewater through solar photocatalytic process

In this study, the photocatalytic degradation of batik wastewater in the presence of zinc oxide (ZnO) as photocatalyst was investigated. The effect of various operating parameters, such as pH of batik wastewater, catalyst dosage and aeration on the photocatalytic degradation process, was examined. The mineralization of batik wastewater was also evaluated through chemical oxygen demand analysis. The decolorization of batik wastewater was enhanced at acidic conditions (pH3) which was 88.2% after 10 h irradiated under solar light, meanwhile its mineralization was 286 mg/L after 12 h irradiation time. The data obtained for photocatalytic degradation of batik wastewater was well fitted with the Langmuir-Hinshelwood kinetic model. It can be concluded that batik wastewater could be decolorized and mineralized under solar light irradiation with presence of ZnO

Optimization of photocatalytic fuel cells (PFCs) in the treatment of diluted palm oil mill effluent (POME)

Photocatalytic fuel cells (PFCs) are considered an advanced technology in wastewater treatment as they are able to remove organic based wastewater by using the principle of advanced oxidation processes (AOPs) and at the same time generate electricity. Despite PFCs being used to treat different types of organic based wastewater efficiently, the use of PFCs in palm oil mill effluent (POME) is still considered rare. Hence, the present research was carried out to determine the optimal conditions of contact time, pH, initial organic concentration and light intensity in order to remove the organic matter present in diluted POME. Our PFC system was constructed by using NaCl as the supporting electrolyte with ZnO/Zn as the photoanode and platinum wire as the cathode. The chemical oxygen demand (COD) removal efficiency and the amount of electricity generated was monitored in different optimization experiments using a conventional fluorescence light source. Under optimal conditions, the COD removal efficiency increased from 7% to 74 %, while the power density output also increased from 1.73 to 35.85 μW/cm2. The PFC was found to work optimally at pH 7 with a light intensity of 1300 lx for 6 h. Meanwhile, the scanning electron microscope (SEM) images revealed the high organic matter concentration in POME can lead to the deposition of an organic layer on the photoanode surface which subsequently reduced the COD removal efficiency to 17.4 %. This result has indicated that PFC is not suitable for treating the fresh POME directly from the mill, but it is more suitable for treating POME, from the last biological treatment pond

Effects of Silane Coupling Agents on the Properties of Copper Filled Electrically Conductive Adhesive

Abstract. Effects of silane coupling agents with different functional groups such as epoxy, isocyanate and ureide on the electrical and mechanical properties of copper filled electrical conductive adhesives (ECAs) were studied. Copper (Cu) fillers were used as conductive fillers and polyurethane resin was applied as the adhesive material in this study. Significant differences could be observed on the as cured electrical resistivity and shear strength of the Cu filled ECAs prepared with different silane coupling agents. Silane coupling agents functionalized with epoxy groups showed the lowest electrical resistivity and highest shear strength among the ECAs in this study. Besides, effect of post-curing at 170°C for 1 h on the ECAs was also investigated. Results showed that ECAs after post-curing exhibited enhanced electrical conductivity compared to the as cured ECAs. Besides, improved shear strength could be observed for all the ECAs after post-curing