Materials Science Forum Vol. 997

Abstract: One of the most significant factors in machining process or metal cutting is the cutting tool performance. The rapid wear rate of cutting tools and cutting forces expend due to high cutting temperature is a critical problem to be solved in high-speed machining process, milling. Near-dry machining such as minimum quantity lubrication (MQL) is regarded as one of the solutions to solve this problem. However, the function of MQL in milling process is still uncertain so far which prevents MQL from widely being utilized in this specific machining process. In this paper, the mechanism of cutting tool performance such as tool wear and cutting forces in MQL assisted milling is investigated more comprehensively and the results are compared in three different cutting conditions which is dry cutting, wet cutting (flooding) and MQL. The MQL applicator is constructed from a household grade low-cost 3D printing technique. The chips surface of chips formation in each cutting condition is also observed using Scanning Electron Microscopy (SEM) machine. It is found out that wet cutting (flooding) is the best cutting performance compare to MQL and dry cutting. However, it can also be said that wet cutting and MQL produced almost the same value of tool wear and cutting forces as there is negligible differences in average tool wear and cutting forces between them based on the experiment conducted.

Abstract: Heterogeneous catalyst has been viewed as a promising catalyst for biodiesel production. This study employed Turritella terebra (TT) shell as a source for synthesizing heterogeneous CaO catalyst for biodiesel production via transesterification by utilizing chicken fat as a feedstock. The TT shell CaO catalyst was characterized and its catalytic performance was studied. The spectrographic methods that include FTIR, SEM, PSA, and BET-BJH were employed for characterization of the synthesized CaO. The TT shell CaO catalyst optimally produced chicken fat biodiesel (CFB) with reaction parameters at catalyst concentration of 4 wt%, chicken fat to methanol molar ratio of 1:12, reaction temperature of 60°C, and reaction time of 90 min. The optimal yield was 94.03% and the TT shell CaO catalyst still yield 79.19% of CFB on the fifth cycle of reaction. This study has implied that TT shell is a feasible and attractive renewable source of heterogeneous CaO catalyst for biodiesel production.

Abstract: The presence of high CO₂ content in natural gas reservoirs is one of the significant threats to the environment. Cryogenic CO₂ capture technology is amongst the emerging technologies used for natural gas purification before customer use. In this research work, the binary CO₂-CH₄ mixture having 75% CO₂ content is studied. Aspen Hysys simulator with Peng Robinson property package is used for the prediction of phase equilibrium data for the binary mixture. The data obtained through the Aspen Hysys simulator is optimized for the S-V two-phase region for maximum CO₂ capture. Response surface methodology is used for the optimization of the predicted data. Optimization of the pressure and temperature conditions is done to obtain maximum CH₄ in the top stream and minimum CO₂ with minimum energy requirement. In this research work, the pressure and temperature ranges selected from the predicted phase equilibrium data for the optimization are 1 to 20 bar and-65 to-150 °C respectively. At atmospheric pressure and-123.50 °C, the desirability value is maximum, which is 0.843. under these conditions, the CO₂ and CH₄ in the top product stream are 1070.72 Kg/hr and 152.04 Kg/hr respectively with an energy requirement of 2.087 GJ/hr.

Abstract: The extensive use of heavy metals such as copper in various industries has discharged a large amount of the metals into the environment which is toxic at higher concentrations. The use of low-cost agricultural waste of biological origin such as tea waste may be an economic solution to this problem. Tea waste is among the potential material to be developed as an adsorbent for heavy metal ions. Tea waste contains cellulose and lignin which have been reported having an excellent metal binding capacity. This study aims to use tea waste for the removal of Cu²⁺ ions. The effect of variation in different parameters like initial concentration of Cu²⁺ ions in solution, adsorbent dosage and contact time were investigated using batch adsorption method. The adsorbent, tea waste was characterized using a compound microscope and FTIR spectroscopy. Experimental results showed that the maximum removal of the copper ion by tea waste at optimum condition (pH 7, 60 min. contact time, 0.8 g adsorbent dose and 0.7 M concentration) is 74%. The adsorbent prepared from tea waste is efficient and it can be conveniently employed as a low-cost alternative in the treatment of wastewater for heavy metal removal.

Abstract: Natural mangrove wetlands located at the transition zone between upland and rivers usually act as an effective pollution buffer due to their function in degrading organic pollutants (BOD) in polluted water. The efficiency of mangrove is often reported based on the percentage of pollutant removals but the associated degradation kinetics have received little attention. This study looks at the pollutant degradation coefficient, k, of mangrove wetlands by on-site experiments at the wetland of the Brunei River, which is dominated by Rhizophera Apiculata and Sonneratia Alba. The mangroves experimented on were enclosed with timber and the pool has retained partially treated wastewater. Water samples were collected at the inlet and in the pool and then tested in several runs of experiments. The typical reaction kinetic model was used to estimate k and it was found that k has a mean and median of 0.43 and 0.47 (day^-1) respectively. The value of k was further modified for saline water conditions and it was estimated to be 0.28 (day^-1) with salinity of up to 20 ppt. These findings provide an insight of the reactions of pollutants in mangroves and can be used in water quality modelling of tropical rivers with mangrove forests.

Abstract: Peat water is an abundant water resource in Sarawak where some of the coastal areas in Sarawak still utilize peat water for domestic usage. Peat water contains natural organic matters especially humic substances which include humic acids. Humic acids contribute to the brown color of peat water and can cause diseases such as stomach cancer, blackfoot disease and etc. if consumed by human. Electrocoagulation is an alternative to conventional water treatment methods which have the advantages of being environmental friendly, minimal sludge production and no addition of chemical substances. The aims of this study are to fabricate a desktop scale electrocoagulation system with galvanised iron electrodes and to investigate the effects of the operating parameters such as inter-electrode distance, applied current density, number of electrodes, and treatment time on peat water in the system. The performance of batch electrocoagulation system in term of their removal efficiency of several parameters such as total organic carbon (TOC), chemical oxygen demand (COD), color and turbidity are evaluated. Through experimental tests conducted, this system successfully removes 98.44% of COD, 92.02% of TOC, 97.92% of turbidity and 99.91% of color by using galvanized iron as an electrode at current density of 25 A/m²in 30 minutes with 10 galvanized iron electrodes. Despite the fact that there is a small amount of iron ions and zinc ions remained in the treated peat water which are 0.001mg/l and 0.0442mg/l respectively, these concentrations are far below the standard limits imposed by Malaysia Ministry of Health (MOH). Generally, all the parameters studied meet the standard limit imposed by MOH except for total organic carbon. This is particularly due to the improper filtration system adopted in this study. The total operating costs for 25² in 30 minutes treatment time of 10 electrode plates is RM 8.75 per . Overall, the study have successfully designed a batch electrocoagulation system to treat peat water by using galvanized iron for domestic usage.

Abstract: Palm oil processing is a multi-stage operation which generates large amount of palm oil mill effluent (POME). Due to its potential to cause environmental pollution, POME must be treated prior to discharge. Electrocoagulation (EC), adsorption (AD), combined EC and AD, and EC integrated with AD have demonstrated great potential to remove various organic and inorganic pollutants from wastewater. Up to date, no study has been found on POME treatment using EC-AD hybrid process. Therefore, this study aims to investigate the feasibility of applying EC-AD hybrid process as an alternative treatment for POME. The EC-AD hybrid process achieved higher removal of total suspended solid (TSS), chemical oxygen demand (COD) and colour as compared to EC and AD stand-alone processes. The EC-AD hybrid process reduced 79% of TSS, 44% of COD and 89% of colour from POME. The adsorption kinetics of TSS, COD and colour were best interpreted using pseudo-second-order model, which indicated that the adsorption rate was mainly controlled by chemisorption. Overall, the EC-AD hybrid process could be recommended as an alternative treatment for POME.