Characteristics of durian shell as support media in biofilter.

Malaysia is an agriculture-based country that produces a lot of agricultural by-products every year. There are potential agriculture by-products yet to be investigated, which can be used as biofilter carriers. This study investigates the physical and chemical characteristics of Durian Shell (DS), an agricultural waste, in assessing its potential to be used as a biofilter media for removing toxic vapors. Ultimate analysis was performed using an elemental analyzer. The presence of functional groups in samples was determined by Fourier Transform Infrared (FTIR) spectroscopy. The powdered DS was mixed with calcium hydroxide (Ca(OH)2) in 23:1 ratio (w/w) dry basis for pH adjustment to be within pH 7-8. The sample was then prepared into a pellet (30 mmØ) by hydraulic hand pressure (5 psi). The specific surface area and average pore size were measured based on Brunauer-Emmet-Teller (BET) method and surface morphology was determined by Scanning Electron Microscope (SEM) analyzer. The results showed that DS has a potential alternative to other carriers, especially peat in term of characteristics, which is not available at a low price or in large quantities in Malaysia

Uptake of Cadmium and Zinc from synthetic effluent by water hyacinth (Eichhornia Crassipes)

In this study was conducted on aquatic plant; water hyacinth (Eichchornia crassipes) which has been successfully utilized for the removal of cadmium (Cd) and zinc (Zn) from aqueous solutions. The overall metal uptake by the plant was dependent upon the concentration of the metal and the duration of exposure. In general, the metal content in plants increased with the increase in metal concentrations in solution and the metal accumulation in roots was always significantly higher than that in shoots for both metals in water hyacinth. Water hyacinth treated with 4 mg/L of cadmium accumulated the highest concentration metal in shoots (148 μg/g) and roots (2006 μg/g) and water hyacinth treated with solution containing 40 mg/L zinc accumulated the highest zinc concentration in shoots (1899 μg/g) and roots (9646 μg/g)

Potential effect of using ultrasonic irradiation to reduce concentration of COD in Palm Oil Mill Effluent (POME)

Many researchers have attempted in the past to look at the possibility of using ultrasonic irradiation or sonication in degrading organic compounds in aqueous wastewater. Ultrasonic irradiation was found to be a safe, clean and effective method for deterioration of specific organic compounds. Ultrasonic irradiation can be used as a stand-alone process, or can be integrated with other treatment methods. However, very limited study focuses on the application of ultrasonic irradiation for treating industrial wastewater; therefore, it is considered as a new research. When water is exposed to ultrasonic irradiation,+H and -OH radicals are produced; the latter is a strong oxidizing agent which can degrade organic pollutants. This study uses raw Palm Oil Mill Effluent (POME) as a test media to investigate the effectiveness of ultrasonic irradiation in reducing organic compounds based on the Chemical Oxygen Demand (COD) concentration at selected operating conditions, namely power density of ultrasonic probe and addition of catalysts. Results showed percentage reduction of COD was highest at power density 29W/L than power density 55W/L. Power density 29W/L of ultrasonic probe chose to combine with catalysts. Application of ultrasonic irradiation with presence of the catalysts CuSO4 and FeSO4, increased the percentage of COD reduction, but FeSO4 gave a better result. The highest percentage reduction of COD of raw POME is around 30% after ultrasonic irradiation process combined with the catalyst FeSO4

Dynamic behaviour of Cd2+ adsorption in equilibrium batch studies by CaCO3 --rich Corbicula fluminea shell

This work presents the structural and adsorption properties of the CaCO3 −-rich Corbicula fluminea shell as a natural and economic adsorbent to remove Cd ions from aqueous solutions under batch studies. Experiments were conducted with different contact times, various initial concentrations, initial solution pH and serial biosorbent dosage to examine the dynamic characterization of the adsorption and its influence on Cd uptake capacity. The characterization of the C. fluminea shell using SEM/EDX revealed that the adsorbent surface is mostly impregnated by small particles of potentially calcium salts. The dominant Cd adsorption mechanism is strongly pH and concentration dependent. A maximum Cd removal efficiency of 96.20 % was obtained at pH 7 while the optimum adsorbent dosage was observed as 5 g/L. The Langmuir isotherm was discovered to be more suitable to represent the experimental equilibrium isotherm results with higher correlation coefficients (R 2 > 0.98) than Freundlich (R 2 < 0.97). The correlation coefficient values (p < 0.01) indicated the superiority of the Langmuir isotherm over the Freundlich isotherm

Effects of ultrasonic irradiation on landfill leachate under different operating conditions.

One of the interesting and promising methods for removal of Total Organic Carbon (TOC) present in the landfill leachate is by the application of ultrasonic waves. The aim of this study is to evaluate the reduction efficiency of TOC by ultrasonic irradiation at different operating parameters, namely, the applied ultrasonic power, pH, initial concentration, presence of saturating gas and addition of catalyst (FeSO4) under sonication (20 kHz). Ultrasound can degrade different kinds of pollutants by combining destruction of the target compounds by free radical reaction and thermal cleavage. Overall, the highest reduction of TOC of 47.15% is achieved at the initial concentration, without addition of FeSO4, at pH of 7.4, temperature of 30 C, the ultrasonic frequency of 20 kHz and power density of 0.188 W/cm3. The results indicate that the ultrasonic alone is not capable of mineralizing the TOC in the landfill leachate due to the high strength and molecular weight of pollutants in the leachate

Estimation of the pesticide exposure during spraying among applicators.

Pesticide exposure used in paddy farming was estimated using whole body dosimetry. The respondents were applicators from Sekinchan, Selangor who participated voluntarily in this study. They were given cotton coveralls to wear before spraying pesticide in the fields. After they had completed their task, the coveralls were collected from pesticide applicators immediately. The coveralls were cut into nine pieces representing parts of the body from shoulder to leg to assess the part of the applicator‘s body that will be exposed the most to pesticide during spraying. Each cutting pieces of the coveralls was extracted using acetone: hexane (1:1) solvent mixture followed by cleanup using C-18 Solid Phase Extraction. The solvent extracts were analyzed for chlorpyrifos using GCMS. The result indicated that different pieces of the coveralls have different concentrations of chlorpyrifos residues. The highest concentration of chlorpyrifos residues was found at the bottom left leg and bottom right leg of the body. Biomonitoring of pesticide exposure was also performed on the same applicators using their urine samples collected four times that is before and within two days after spraying. The result showed that 2,3,6 trichloro 2-pyridinol (TCP), a chlorpyrifos metabolite was detected in the urine samples