Phosphate removal from water by polysulfone ultrafiltration membrane using PVP as a hydrophilic modifier

The phosphate removal from aqueous solution was studied with a dead-end filtration process using ultrafiltration membranes. Polysulfone (PSf) ultrafiltration membranes were prepared by blending PSf with polyvinylpyrrolidone (PVP). The prepared membranes were characterized by water content, contact angle, SEM, EDX, AFM, and FTIR. The hydrophilicity and porosity of membrane improved considerably and water contact angle declined with the incorporation of PVP. While pure PSf membrane did not have any flux, PSf/PVP 3 wt.% (UF2) shows 9.6 L/m2 h permeate flux. The impact of diverse operating parameters, such as PVP concentration, pressure, and pH of the feed solution on the removal of phosphate was examined. A high phosphate removal (93.6%) from aqueous solution was observed for UF2 membrane and 87.2% for UF3 membrane at feed solution pH 2. It was found that the phosphate rejection dropped as the pressure and PVP concentration increased. A reduction in pH of the feed solution gave a higher phosphorus rejection

Preparation and characterization of polysulfone / zeolite mixed matrix membranes for removal of low concentration ammonia from aquaculture wastewater

Removal of low-concentration ammonia (1-10 ppm) from aquaculture wastewater was investigated via polysulfone (PSf)/zeolite mixed matrix membrane. PSf/zeolite mixed matrix membranes with different weight ratios (90/10, 80/20, 70/30 and 60/40 wt.%) were prepared and characterized. Results indicate that PSf/zeolite (80/20) was the most efficient membrane for removal of low-concentration ammonia. The ammonia elimination by PSf/zeolite (80/20) from aqueous solution for 10, 7, 5, 3 and 1 ppm of ammonia was 100%, 99%, 98.8%, 96% and 95% respectively. The recorded results revealed that pure water flux declined in higher loading of zeolite in the membrane matrix due to surface pore blockage caused by zeolite particles. On the other hand, ammonia elimination from water was decreased in higher contents of zeolite because of formation of cavities and macrovoids in the membrane substructure

A COMPARATIVE STUDY OF QUADRILATERALS TOPIC CONTENT IN MATHEMATICS TEXTBOOKS BETWEEN MALAYSIA AND SOUTH KOREA

This study compares Malaysian and Korean geometry content in mathematics textbooks to help explain the differences that have been found consistently between the achievement levels of Malaysian and South Korean students in the Trends in International Mathematics and Science Study (TIMSS). Studies have shown that the use of textbooks can affect students’ mathematics achievements, especially in the field of geometry. Furthermore, to date, there has been no comparison of geometry content in Malaysian and Korean textbooks. Two textbooks used in the lower secondary education system in Malaysia and South Korea were referred. The topic of quadrilaterals was chosen for comparison, and the topic’s chapter in the South Korean textbook has been translated into English. The findings show four main aspects that distinguish how quadrilaterals are taught between the two countries. These aspects include the composition of quadrilaterals topics, the depth of concept exploration activities, the integration of deductive reasoning in the learning content and the difficulty level of mathematics problems given at the end of the chapter. In this regard, we recommend the Division of Curriculum Development of the Malaysian Ministry of Education reviews the geometry content of mathematics textbook used today to suit the curriculum proven to produce students who excel in international assessments

Heterogeneous photocatalytic degradation of organic contaminants over titanium dioxide: A review of fundamentals, progress and problems

Even though heterogeneous photocatalysis appeared in many forms, photodegradation of organic pollutants has recently been the most widely investigated. By far, titania has played a much larger role in this scenario compared to other semiconductor photocatalysts due to its cost effectiveness, inert nature and photostability. Extensive literature analysis has shown many possibilities of improving the efficiency of photodecomposition over titania by combining the photoprocess with either physical or chemical operations. The resulting combined processes revealed a flexible line of action for wastewater treatment technologies. The choice of treatment method usually depends upon the composition of the wastewater. However, a lot more is needed from engineering design and modelling for successful application of the laboratory scale techniques to large-scale operation. The present review paper seeks to offer an overview of the dramatic trend in the use of the TiO2 photocatalyst for remediation and decontamination of wastewater, report the recent work done, important achievements and problems

Synthesis and characterization of zinc oxide/maghemite nanocomposite: influence of heat treatment on photocatalytic degradation of 2,4-dichlorophenoxyacetic acid

In the current study, ultraviolet-active zinc oxide/maghemite (ZnO/γ-Fe2O3) nanocomposite catalysts were prepared and applied to the photodecomposition of 2,4-dichlorophenoxyacetic acid (2,4-D). 2,4-D is a herbicide that is widely used in agriculture and landscape turf management. The ZnO/γ-Fe2O3 nanocomposite catalyst was prepared using a simple and efficient precipitation–thermal decomposition method. Comprehensive experimental studies and characterizations such as X-ray diffraction (XRD), TEM, Brunauer–Emmett–Teller (BET) and UV–vis diffuse reflectance spectrum (UV-DRS) analyses were conducted to optimize the photoactivity of the nanoparticles. Interestingly, the synthesized ZnO/γ-Fe2O3 nanocomposite catalyst exhibited a hexagonal phase with wurtzite structure, and their active surface area decreased with increasing calcination temperature. Based on the TEM micrographs, the appearance of the ZnO/γ-Fe2O3 nanocomposite catalyst is nearly spherically shaped with a mean particle size in the range of 13–35 nm. The nano-ZnO/γ-Fe2O3 that underwent heat treatment at 450 °C exhibited better photodecomposition of 2,4-D, which was primarily due to the highest specific surface area and the smallest particle size among the synthesized samples

Power Generation From Biomass Fluidized Bed System

Present energy use is largely dependent on fossil fuels which make future sustainable development very difficult. Fossil fuels contain high amount of carbon dioxide (CO2) and sulphur dioxide (SO2) that may cause air pollution and global warming. Biomass fuels appear as the most suitable option to substitute the fossil fuels with the highest general worldwide potential. Fluidized Bed Gasifier (FBG) is one of the conversion techniques that can be used to converse the biomass into useful and clean gasses. This system has been designed at Universiti Sains Malaysia for researching process related. The present work reports studies on the previous researches on fluidized bed and the development process of the designed system. The design parameters of fluidized bed are also studied for further understanding. The development process is including the piping installation of the system and the modification of the system. The modifications carried out depending of the problems occur after the piping installation. Most of the modification carried out focused on the gas inlet port connection. Besides, some experiments are also carried out in order to determine the bed material (sand) size, the density and the moisture content of wood chip fuel. Sands and wood chip are used in running the gasifier system. The results of the experiment then are compared with the design parameter to ensure either the sand purchased suitable for the gasifier experiment or not

Low-temperature synthesis of ZnO by wet chemical method

Zinc oxide (ZnO) wire was synthesized by hydrothermal method at 70° C by using Zn acetate dihydrate and ammonium hydroxide as the starting material. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron disperse X-ray (EDX), electro diffraction (ED) and transmission electron microscopy (TEM). The XRD result confirmed the formation of ZnO with wurtzite structure. The ED reveals that ZnO wire is single crystal and grows up along [001] direction. Influence of temperature on crystal growth was evaluated. Results shown that increase in temperature shorten the length of wire

The importance of metacognition in physics problem solving: monitoring skills

The purpose of this paper is to show the importance of metacognitive skills in solving force and motion problem. This study consists of 10 students and students were divided into 2 groups based on their test score. One group were classified as more successful (MS) problem solvers and the other one as less successful (LS) problem solvers. Students solved physics problems while talking aloud. Each of the students were videotaped. Interviews were conducted right after the test. Written answers from physics task were marked according to the schema. In this paper, findings from one question were discussed. The question called “lift’ problem. The thinking aloud were transcribed verbatim from the videotapes as well as interviews. Transcripts were coded and examined looking for both similarities and differences. As a conclusion, monitoring were shown as an important metacognitive skills in physics problem solving

A Modular Command and Data Handling System Concept for Small Satellites

The increasing demand for high-performance computer systems on board space missions applications, such as artificial intelligence and machine learning, are drivers of the need for higher on-board command and data handling specifications. Consequently, a modular Command and Data Handling Subsystem (CDHS) is required in order to manage the complexity of future CDHS hardware. Some systems have applied a similar approach; however, they either focus on large scale satellites or have a certain level of complexity that limits their usage by learners. This paper proposes a modular Command and Data Handling System that includes several layers providing more flexibility in design at a low cost. The system also potentially allows the integration of CDHS initially used in CubeSats in larger-scale satellites. Also, Through this paper highlights the interfacing options used in the proposed design, including the regular command and data interfaces, wireless command and data interfaces, high-speed data interfaces, and power interfaces. The results validate the usefulness and potential of the proposed system as a modular Command and Data Handling System that can be used in future missions. It also opens the door for further development, allowing the low-cost development of Command and Data Handling Systems