Microalgae-based products have gained growing interest leading to an increase in large-scale cultivation. However, the high energy associated with microalgae harvesting becomes one of the bottlenecks. This study evaluated an energy-efficient microalga harvesting via ultra-low-pressure membrane (ULPM) filtration (<20 kPa) in combination with aeration. ULPM offered various benefits especially in terms of reducing the energy consumption due to it operated under low transmembrane pressure (TMP). High TMP often associated with high pumping energy hence would increase the amount of energy consumed. In addition, membrane with high TMP would severely affect by membrane compaction. Results showed that membrane compaction leads to up to 66 % clean water permeability loss when increasing the TMP from 2.5 to 19 kPa. The Chlorella vulgaris broth permeabilities decreased from 1660 and 1250 to 296 and 251 L/m 2 hrbar for corresponding TMPs for system with and without aeration, respectively. However, it was found that membrane fouling was more vulnerable at low TMP due to poor foulant scouring from a low crossflow velocity in which up to 56 % of permeability losses were observed. Membrane fouling is the biggest drawback of membrane system as it would reduce the membrane performance. In this study, aeration was introduced as membrane fouling control to scour-off the foulant from membrane surface and pores. In terms of energy consumption, it was observed that the specific energy consumption for the ULPM were very low of up to 4.4 Â 10 À3 kWh/m 3 . Overall, combination of low TMP with aeration offers lowest energy input.
The previous biodiesel purification by Solvent-Aided Crystallization (SAC) using 1-butanol as assisting agent and parameters for SAC were optimized such as coolant temperature, cooling time and stirring speed. Meanwhile, 2-Methyltetrahydrofuran (2-MeTHF) was selected as an alternative to previous organic solvents for this study. In this context, it is used to replace solvent 1-butanol from a conducted previous study. This study also focuses on the technological improvements in the purification of biodiesel via SAC as well as to produce an even higher purity of biodiesel. Experimental works on the transesterification process to produce crude biodiesel were performed and SAC was carried out to purify the crude biodiesel. The crude biodiesel content was analyzed by using Gas Chromatography–Mass Spectrometry (GC-MS) and Differential Scanning Calorimetry (DSC) to measure the composition of Fatty Acid Methyl Esters (FAME) present. The optimum value to yield the highest purity of FAME for parameters coolant temperature, cooling time, and stirring speed is −4 °C, 10 min and 210 rpm, respectively. It can be concluded that the assisting solvent 2-MeTHF has a significant effect on the process parameters to produce purified biodiesel according to the standard requirement.
Membrane distillation crystallization (MDC) is a promising hybrid separation technology that can play an important role in desalination, mineral recovery from liquid solution as well as in carbon dioxide fixation. MDC combines membrane distillation and crystallizer into one integrated unit that allows excellent recovery of clean water and high purity salt from highly concentrated salts solution (i.e., brine), which is otherwise detrimental when discharged to the environment. The process intensification addresses the limitation of standalone membrane distillation and a standalone crystallizer (i.e., temperature and concentration polarization, membrane properties) when operated as individual technology. This review discusses the fundamental of MDC focused on how the process intensification addresses those standalone units' limitations. Later, MDC's potential applications in addressing some pressing issues such as water scarcity and climate change are also evaluated. Lastly, current trends in the MDC research are discussed to project the required future developments.
The development of engineering education plays a significant role in creating a competency base for engineering students to be excellent in engineering practice as well as other professional skills such as communication, teamwork and leadership. Project-Based Learning via Integrated Project entitled Heat Recovery from Ammonia Synthesis Reactor for Power Generation was introduced as a new learning approach for First Year First Semester Chemical Engineering student to replace the conventional learning approach via lecture. This integrated project is a hybrid of two core Chemical Engineering subjects for First Year students: Chemical Engineering Thermodynamics I and Process Heat Transfer. This integrated project aims to evaluate students' ability to relate two different subjects when learning in the same semester and apply them to the same application. This integrated project is expected to enhance students' learning curve and ensure that the output of this study can be achieved in a consistent effort and timely manner. Assessments in the form of formative (reflection and peer review) and summative (final report) are applied to the students via individual and group. Based on the reflection's analysis, 50% of the students mentioned that the project is very challenging; meanwhile, only 30% agreed that they could relate the project with both subjects even though it is complex and challenging. Despite that, 70% of the students stated that their learning goal is achievable. They were able to view the industrial application, especially the heat exchanger application, through this project. Overall, 90% agreed that they achieved this integrated project's objectives: to relate two different subjects when learning in the same semester and apply them to the same application. Hence, it is noteworthy to highlight that this integrated project is carefully mapped. The new learning approach via Project-Based Learning brought positive outcome towards the students' learning experiences, skills and understanding.
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