Aluminum waste-can management in Malaysia has recently become a serious environmental and public health issue, particularly in metropolitan areas. This has prompted the need to valorize these waste-cans into value-added products using the most economical and environmentally friendly techniques. In this study, the sol–gel technique was used to synthesize high-quality alumina from the aluminum waste-cans collected. From this method, the observed peaks of the synthesized alumina were identified as diaspore (α-AlO(OH)), boehmite (γ-AlO(OH)), aluminum oxide, or gamma-alumina (γ-Al₂O₃) crystalline structure and corundum. The morphological configuration, microstructure, and functional group properties of the synthesized alumina were evaluated. All the synthesized alumina exhibited a non-spherical shape and appeared to have hexagonal-like shape particles. Moreover, the XRD patterns of the synthesized alumina AL-6-30 and AL-12-30 exhibited a small angle (1–10°) with no XRD peak, which indicated a mesoporous pore structure with no long-range order. The overall results of γ-alumina synthesized from the aluminum waste-cans showed an optimal condition in producing a highly structured γ-alumina with excellent surface-area characteristics. The synthesized alumina exhibited stronger and highly crystalline functional characteristics almost comparable with the commercially available brands on the market.

Butene-1 is an essential compound or co-monomer typically used to regulate and control the density of both high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). The production of Butene-1 has become a significant area of interest to the industrial and educational-research sectors. Alphabutol technology is one of the Butene-1 production processes. This paper attempts to find a problem that has not been addressed by previous research on production of Butene-1 by using ethylene demineralization route focussing on Alphabutol Technology. The first part of this paper is on the ethylene dimerization techniques available in the literature. Most research on the ethylene dimerization technique emphasized on how to enhance the selectivity of Butene-1 from ethylene using different types of catalyst. The second part of this paper reviews the operational processes used to minimise fouling reported in the literature review. Most of the literatures focused ethylene dimerization and not on the operational issues to be overcome during chemical reactions to enhance the selectivity of Butene-1. Fouling problem in Alphabutol process is still an area that is not adequately addressed in the literature. There is also no literature on operating or maintenance procedure to address these problems of the technology. Therefore, there is still room for improvement on the ethylene dimerization research technology, particularly in the operational process and conditions where the improvement in the reaction parameters of the Alphabutol reactor can improve selectivity of butene-1, extend the run time of the heat exchanger and reduce the time required to clean the heat exchanger fouling.

Taguchi orthogonal design was used in this study to investigate the effects of three operational parameters (i.e., reactor temperature, reactor pressure, and catalyst ratio on per‐pass conversion (PPC)). The optimal PPC was calculated from the predicted response function at 48°C of reactor temperature, 21 kg/cm ² g of reactor pressure, and catalyst mole ratio of 2.50. Under these conditions, the PPC was estimated to be 87.1 per cent, with a maximum SNR of 38.95. In line with the delta ranking, the decreasing order of significance of each process parameter on the average per‐pass conversion (PPC) was x ₁ > x ₂ > x ₃ , with percentage contributions of 50.6%, 26.1%, and 23.3% for reactor temperature, temperature, and catalyst mole ratio, respectively. The optimal production condition can therefore be attained at a larger scale with the higher per‐pass conversion of butene‐1.

In this study, different operating parameters which contributed to the fouling formation were identified, while taking into consideration the heat and mass and balance. The effects of three operational parameters viz: reactor temperature, reactor pressure, andcatalyst ratio, feed to and out of reactor and heat exchanger cleaning time on the optimal yield were succinctly investigated using an empirical mathematical model. The optimum per pass conversion (PPC) that maximizes yield and extends pump around loop (PAL) days in service was obtained using the analytic hierarchy process (AHP). The result obtained under the optimum operational condition shows an increased yield from 84 to 85.5% and a 1% improvement in the 1‐butene selectivity. Moreover, due to the decrease in maintenance activities, production increased by 1000 tons per annum. In addition to this, the cleaning cycle of the pump around the loop was extended by 9 days and the man‐hour cleaning requirement was reduced by 91 days. The operating time of the pump around the loop increased by 30 days per loop with a corresponding reduction in the cleaning time of 50 h which resulted in maximum yield. This study, therefore, presented a design from the sensitivity analysis conducted with the potential benefit of informed decision‐making in the process of making a trade‐off between optimizing variable cost with the cost of maintaining the Alphabutol technology.

The feasibility of recovering bioactive antioxidants from Phyllantus emblica leaves using ethanol -water mixture (0 – 100%) and heat-assisted extraction technology (HAE-T) was investigated in this present study. To this effect, the process parameter of operating temperature (OT: 30 -50 oC), solid -to-liquid ratio (S:L: 1:20 - 1:60 g/mL) and extraction time (ET: 45 - 180 min) were investigated on the extract total phenolic content (TPC, mg GAE/g d.w), yield (EY, %) and antioxidant activity (μM AAE/g d.w) by employing the Box-Behnken experimental design (BBD) available in response surface methodology (RSM). Multi-objective process optimization using the desirability function algorithm to determine set of process variables that simultaneously optimize process responses of TPC, EY and AA was also investigated. The recovery process was thereafter modeled with BBD-RSM and multi gene genetic programming (MGGP) algorithm and model reliability assessment via Monte Carlo simulation were conducted for the best performing set of models for predicting TPC, EY and AA values. The HPLC characterization of the recovered extract was carried out to ascertain the phenolic compound constituents of the Phyllantus emblica leaf extract. The 50% ethanol solution was found to be the best for the optimal extraction of antioxidants from Phyllantus emblica leaves. The HAE-T was suitable for recovering bioactive extract from Phyllantus emblica leaves and investigated process parameters have impacts on the recovery process. The process parameters that simultaneously gave the optimum EY of 21.6565%, TPC of 67.116 mg GAE/g and AA of 3.68583 µM AAE/g were OT of 41.61 oC, S:L of 1:60 g/mL and ET of 180 min. The HPLC extract profiling revealed that the bioactive constituents present in the recovered extract were betulinic acid, gallic acid, chlorogenic acid, caffeic acid, ellagic acid, and ferulic acid. Both the developed BBD-RSM and evolved MGGP-based models predicted the observed process response of TPC, EY and AA satisfactorily with BBD-RSM models marginally better in their predictions. The reliability results showed that the BBD-RSM models predicted TPC, EY and AA values with high certainty of 99.985%, 97.569% and 98.661%, respectively.