Abdul Rajak

Photocatalytic Activities of Electrospun TiO2/Styrofoam Composite Nanofiber Membrane in Degradation of Waste Water

TiO2/Styrofoam composite fiber membranes were synthesized by using an electrospinning system for water purification applications. Composite fiber membrane was fabricated from precursor solution prepared by dissolving Styrofoam in the mixture of tetrahydrofuran (THF), citronella oil and cajuput oil. The precursor solutions is mixed with TiO2 powder with three variations based on the concentration (1:15,1:20 and 1:40). Textile dye with 50 ppm of concentration was performed as a model of waste water. The structure and morphology of each membrane were characterized by using scanning electron microscopy (SEM). The photocatalytic activity was investigated under the bulb light with 60 watt of power in the box of photocatalytic test. Observation of photocatalytic process were performed for 30 hours. The quantitative data of the decrease in the concentration of wantex solution were measured by using UV-Vis spectrometer and simple spectrometer which was developed recently. It was shown that there are significant decrease of the concentration of wantex solutions performed by each membrane. As many as 69% of wantex solution have been successfully degraded for 30 hours under the bulb light.

A Simple Spectrometer Using Various LEDs and a Photodiode Sensor for Photocatalytic Performance Evaluation

The degradation of pollutants in a waste water with the aid of light as an energy source enabler is one of the photocatalysis processes. Because a textile dye dissolved in water is often used to model the waste water, the degradation of color becomes a major variable to indicate the water clarity after the photocatalysis process occured. Therefore, a sensitive instrument to measure the degradation of color is required. This paper reports a simple spectrometer using a photodiode sensor OPT101 and a light emitting diode (LED). The light emitted by the LED passes through the waste water so that its intensity is reduced. Then, the photodiode sensor receives the light with reduced intensity. In order to test the spectrometer performance, a waste water model was prepared by employing a textile dye in water with various concentrations. Curves showing the relationships between concentration and voltage output of the sensor were obtained for different colors of LEDs (white, blue, orange, red and yellow). A microcontroller is used to process the voltage output of the sensor and an LCD then displays the concentration. The results shows that red LEDs has a smallest error with an error of less than 5%.

Measurement of Glucose in Blood Using a Simple Non Invasive Method

The amount of glucose in blood of human beings should be controlled. The excess or deficiency in glucose of human blood can cause a variety of diseases such as diabetes, heart disease, cholesterol and blindness. We report the design and development of a simple spectrometer as a non-invasive method to determine glucose in urine. Note that glucose in urine, which is caused by exceeding glucose level from the threshold in the renal system, is correlated with that in blood since glucose is a part of acid hydrate in the digestive tract and is absorbed by the intestine in the blood circulation. Urine containing glucose is reacted with a benedict solution that in turn affects the turbidity of urine according to the glucose concentration in the urine. Urines with various turbidities were then placed in transparent containers sitting between a light emitting diode (LED) as a light source and a photodiode as a detector of the simple spectrometer. As the concentration of glucose in the mixture solution became higher, the mixture solution developed more turbid and the output voltage of the photodiode would then be smaller. Moreover, the color of LED affects the magnitude of light intensity that can be transmitted by the sample.

A Computer-Based Air Flow Control System for Aerosol and Filtration Research

An airflow control system is one of important parts in the scanning mobility particle sizers system (SMPS) used in the field of aerosol and air filtration. In this paper, the air flow control system that consists of an air filter, a blower, an air flow sensor, a controller, and a computer are reported. A flow rate adjustment was performed by varying the rotation speed of the blower using a pulse width modulation (PWM) technique. The air flow sensor capable of measuring flow rate up to 20 liters / min was used to measure the air flow rate. In order to keep at a certain value of the flow rate, a proportional-integral-derivative (PID) control action was employed in which PID controller were manually tune. The results showed that the desired value of flow rate was quickly achieved with little overshoot was observed in the system output.