Metakaolin is a commonly used aluminosilicate material for the synthesis of geopolymer based adsorbent. However, it presents characteristics that restrict its uses such as weak rheological properties ...brought on by the plate-like structure, processing challenges, high water demand and quick hydration reaction. Industrial waste, on the other hand, contains a variety of components and is a potential source of aluminosilicate material. Geopolymer adsorbent synthesized by utilizing industrial waste contains a wide range of elements that offer better ion-exchangeability and increase active sites on the surface of geopolymer. However, limited studies focused on the synthesized of geopolymer based adsorbent by utilizing industrial waste for heavy metal adsorption in wastewater treatment. Therefore, this paper reviews on the raw materials used in the synthesis of geopolymer for wastewater treatment. This would help in the development of low cost geopolymer based adsorbent that has a great potential for heavy metal adsorption, which could deliver double benefit in both waste management and wastewater treatment.
Rapid development of advanced technology in Malaysia gave impact increasing in the accumulation of heavy metal every day in our daily life through wastewater. Long term exposure of human bodies to ...heavy metals susceptible to receives various infections and diseases. From an environmental and economic perspective, adsorption is acceptable process that can be applied in wastewater treatment. However, usage of activated carbon most acknowledged and costly adsorbents lead people to find an alternative to activated carbon. Several studies of physical properties of geopolymer make them gain attention to replace an activated carbon in the treatment of heavy metal. This paper review adsorption of heavy metal by using geopolymer.
The main problem with existing desalination technologies is that they consume high input energy to generate fresh water. Secondly, this energy demand is usually met by conventional sources of energy ...such as fossil fuels. With limited conventional energy reserves predicted for the future, the focus is on the utilization of renewable sources of energy such as solar, wind, and geothermal energy for powering desalination systems. Such a transformation would make the desalination systems more energy efficient, sustainable, and economical. In this paper, a novel concentrated solar powered (CSP) flash desalination system with direct heating and pressure modulation is presented. A lab-scale prototype was designed, manufactured, and tested for feed water collected from the Arabian Sea and in climatic conditions of Al-Khobar city in Saudi Arabia. The effect of three process parameters, namely, feed water temperature (30–40 °C), feed water flow rate (0.003–0.006 kg/s), and vacuum pressure (0.1–0.3 bar) on distillate production, was investigated. System modelling and optimization were done using Design Expert software and Response Surface Methodology (RSM). The central composite design technique was employed for the optimization of process parameters. The adequacy of the developed distillate production model was verified by ANOVA. The optimum values of feed water temperature, flow rate, and vacuum pressure are reported to be 40 °C, 0.005 kg/s, and 0.1 bar, respectively, resulting in distillate production of 0.001 kg/s.
This paper investigates the impact of various copper (Cu) pillar bump heights on temperature distribution, deformation and thermal stress during reflow. The virtual reflow oven environment was ...simulated using the fluid domain of the oven model. The accuracy of the fluid analysis was verified by comparing the obtained results with experimental data, which was conducted based on the Joint Electron Device Engineering Council (JEDEC) Standard. In addition, a grid independence test was carried out on the fluid mesh to determine the optimal mesh size for the simulations. A thermal fluid–structure interaction (FSI) approach was employed to couple the thermal results from the fluid analysis with the solid assembly. The results of the coupling analysis revealed that Cu pillar bumps with a height of 0.09 mm exhibited the lowest reflow temperature, minimal maximum deformation, and thermal stress, indicating that it is the optimal potential height for forming a good joint. The study also examines the impact of soldering materials, such as tin-bismuth (SnBi) and tin-silver-copper solder alloys (SAC305 and SAC405), on the Cu pillar bump. This study enables a comprehensive analysis of the thermal and mechanical performance of different Cu pillar bump parameters during the reflow process.
This study involved synthesising new hybrid polymers called ZOPAT, made up of zinc oxide, acrylamide, and tannin, using a blended technique. The effectiveness of ZOPAT in treating textile wastewater ...was then tested by measuring floc growth rate, flocculation index, strength factor, and recovery factor under optimised conditions. The study also identified the zeta potential, morphology, elemental composition, and functional groups of the polymers. Response surface methodology determines the optimal pH and ZOPAT dose, resulting in 93% colour, 80% chemical oxygen demand (COD), 100% turbidity, and suspended solids (SS) removal at pH 9.22 and 737 mg/L ZOPAT. The study found that ZOPAT was more effective than commercial Polyaluminium chloride in reducing colour and COD, producing larger and stronger flocs, and requiring a shorter coagulation time of 17.5 min. ZOPAT was also easy to homogenise and operate due to its one-unit dosing system. The study attributes the success of ZOPAT to the presence of Zn, N, and K, which create electrostatic attraction with opposite charged particles, and the formation of dye-particle-dye with amide, hydroxyl, and carboxyl groups in ZOPAT, which remove colour, turbidity, COD, and SS. Overall, the study concludes that ZOPAT has significant potential for textile wastewater treatment.
Activated carbon (AC) has received a lot of interest from researchers for the removal of heavy metals from wastewater due to its abundant porous structure. However, it was found unable to meet the ...required adsorption capacity due to its amorphous structure which restricts the fundamental studies and structural optimization for improved removal performance. In addition, AC is not applicable in large scale wastewater treatment due its expensive synthesis and difficulty in regeneration. Thus, the researchers are paying more attention in synthesis of low cost geopolymer based adsorbent for heavy metal removal due its excellent immobilization effect. However, limited studies have focused on the synthesis of geopolymer based adsorbent for heavy metal adsorption by utilizing industrial sludge. Thus, the aim of this research was to develop metakaolin (MK) based geopolymer adsorbent with incorporation of two types of industrial sludge (S1 and S3) that could be employed as an adsorbent for removing copper (Cu2+) from aqueous solution through the adsorption process. The effects of varied solid to liquid ratio (S/L) on the synthesis of metakaolin/sludge based geopolymer adsorbent and the removal efficiency of Cu2+ by the synthesis adsorbent were studied. The raw materials and synthesized geopolymer were characterized by using x-ray fluorescence (XRF), x-ray diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and micro XRF. The concentration of Cu2+ before and after adsorption was determined by atomic absorption spectroscopy (AAS) and the removal efficiency was calculated. The experimental data indicated that the synthesized geopolymer at low S/L ratio has achieved the highest removal efficiency of Cu2+ about 99.62 % and 99.37 % at 25 %:75 % of MK/S1 and 25 %:75 % of MK/S3 respectively compared to pure MK based geopolymer with 98.56 %. The best S/L ratio for MK/S1 and MK/S3 is 0.6 at which the reaction between the alkaline activator and the aluminosilicate materials has improved and enhanced the geopolymerization process. Finally, this work clearly indicated that industrial sludge can be utilized in developing low-cost adsorbent with high removal efficiency.
Rapid global economic development, population growth, and increased motorization have resulted in significant issues in urban traffic safety. This study explores the intrinsic connections between ...road environments and driving safety by integrating multiple visual landscape elements. High-resolution remote sensing and street-view images were used as primary data sources to obtain the visual landscape features of an urban expressway. Deep learning semantic segmentation was employed to calculate visual landscape features, and a trend surface fitting model of road landscape features and driver fatigue was established based on experimental data from 30 drivers who completed driving tasks in random order. There were significant spatial variations in the visual landscape of the expressway from the city center to the urban periphery. Heart rate values fluctuated within a range of 0.2% with every 10% change in driving speed and landscape complexity. Specifically, as landscape complexity changed between 5.28 and 8.30, the heart rate fluctuated between 91 and 96. This suggests that a higher degree of landscape richness effectively mitigates increases in driver fatigue and exerts a positive impact on traffic safety. This study provides a reference for quantitative assessment research that combines urban road landscape features and traffic safety using multiple data sources. It may guide the implementation of traffic safety measures during road planning and construction.
Subsurface perforated pipes drain infiltrated stormwater runoff while attenuating the peak flow. The Manning roughness coefficient (n) was identified as a fundamental parameter for estimating ...roughness in various subsurface channels. Hence, in this work, the performance of a six-row non-staggered sand-slot perforated pipe as a sample of the subsurface drainage is investigated experimentally in a laboratory flume at Universiti Sains Malaysia (USM) aimed at determining the Manning roughness coefficients (n) of the pipe and assessing the relationship between the Manning’s n and the hydraulic parameters of the simulated runoff flow under the conditions of the tailgate channel being opened fully (GFO) and partially (GPO), as well as the pipe having longitudinal slopes of 1:750 and 1:1000. Water is pumped into the flume at a maximum discharge rate of 35 L/s, and the velocity and depth of the flow are measured at nine points along the inner parts of the pipe. Based on the calculated Reynolds numbers ranging from 38,252 to 64,801 for both GFO and GPO conditions, it is determined that most of the flow in the perforated pipe is turbulent, and the calculated flow discharges and velocities from the outlets under GFO are higher than the flow and velocity rates under GPO with similar pipe slopes of 1:750 and 1:1000. The Manning coefficients are calculated at nine points along the pipe and range from 0.004 to 0.009. Based on the ranges of the calculated Manning’s n, an inverse linear relationships between the Manning coefficients and the flow velocity under GFO and GPO conditions are observed with the R2 of 0.975 and 0.966, as well as 0.819 and 0.992 resulting from predicting the values of flow velocities with the equations v = ((0.01440 − n)/0.009175), v = ((0.01330 − n)/0.00890), v = ((0.02007 − n)/0.01814), and v = ((0.01702 − n)/0.01456) with pipe slopes of 1:750 and 1:1000, respectively. It is concluded that since the roughness coefficient (Manning’s n) of the pipe increases, it is able to reduce the flow velocity in the pipe, resulting in a lower peak of flow and the ability to control the quantity of storm water in the subsurface urban drainages.
Debris flow is a devastating phenomenon that happens in hilly and mountainous regions and has a serious impact on affected areas. It causes casualties and serious damage to the environment and ...society. Therefore, a susceptible assessment is necessary to prevent, mitigate, and raise awareness of the impact of debris flows. This paper focuses on evaluating the deposition area along the deposition board. The methodology involved an experiment on a physical model by demonstrating the debris flow based on the steepness of the flume slope at 15°, 20°, and 25° angles. The limestone particles with a total volume of 2.5 × 106 mm3 acted as debris and were released with water from the tank to the deposition board with an area of 10 × 105 mm2. The volume, area, and length of particle distribution carried from the flume to the deposition board were then determined. Based on the experimental results, the deposition board is covered with particles of about 696.19 × 103 mm3, 748.29 × 103 mm3, and 505.19 × 103 mm3 volume for each 15°, 20°, and 25° angle, respectively. In actual situations, debris flow is capable of causing significant risk to the affected area. This study can be deemed useful for a risk assessment approach, to help develop guidelines, and to mitigate the regions where debris flows are most probable to occur.
In Malaysia, there are some accumulation of sugar refinery byproducts with a lot of this material not being utilized in a productive manner, while, these byproducts had the great potential when mixed ...into agricultural soils as organic fertilizer with many of benefits that can improve soil health, and sustainable agronomic productivity. Pressmud or known as filter cake is a by-product of sugar industry and for every 100 tons of sugarcane crushed about 3 tons of pressmud cake is left behind as by-product. This studies carried out on this material have not properly summarized their characteristics properties that they can be used as aid for future works. Data from tests involving pressmud samples from Malayan Sugar Manufacturing (MSM) Prai Berhad, Penang which was part of a larger collection was analyzed. The physicochemical properties of pressmud characterization as well as leaching test were carried out. The physicochemical and engineering properties involved compaction behavior, permeability, cation exchange capacity (CEC), compressive stress test and its surface functional groups. The leaching test method included batch equilibrium test and column test. The optimum value of water content in pressmud was determined in the compaction test. It was found out that pressmud has higher optimum water content value was observed. The permeability test of pressmud gave value in ranges of 1.84 x 10-5 cm/s. The Cation Exchange Capacity (CEC) of pressmud indicated value in the range of 99 to 101 meq/100 g. The high cation exchange capacity indicated that pressmud was believed to be primarily responsible for sorption of metal ions. It can be concluded that pressmud having the capability to remove heavy metals through CEC process. Pressmud also showed higher compressive strength value. Batch equilibrium test glaringly showed that pressmud have the capability to remove from 53.6%-93.8% metal removed from metal solutions for Chromium (Cr), Copper (Cu), Manganese (Mn), Nickle (Ni), Lead (Pb) and Zinc (Zn). From the result of column test, pressmud alone was able to retain efficiently all the heavy metals as these metals did not reach 1 (relative concentration) until 10 pore volume (PV.) indicating that pressmud was a good mixture material as it can assist in adsorption of heavy metals. Based on the characterization study, removal efficiency and column test, pressmud has great potentiality to be used as an additional material in soil amendments to enhance soil fertility and strength ability.
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