Engineering Headway Vol. 25

Abstract: The crude oil sample from Duri and Minas oil well (OSM-1) was fractionated into saturated and aromatic hydrocarbon and residu. The saturated hydrocarbon were characterized by using gas chromatografi (GC), whereas aromatic hydrocarbon were determined by gas chromatography-mass spectrometry (GC-MS). The biomarker composisiton indicated that Duri and Minas crude oil was derived from higher plant (terrestrial) with high wax content for Duri and lower for Minas, it also showed that Minas crude oil was deposit from difftrent deposional environment conditions. The thermal maturity of Minas crude oil was determined by maturity parameters from aromatic hydrocarbons such as methylpenantrene index (MPI) and vitrinite reflectance equivalent (VRE). The result indicated that the crude oil from Minas oil well (OSM-1) has value of MPI-1, MPI-2, MPI-3 and VRE of 0.82, 0.89, 1.02 and 0.89% respectively. The showed that Minas Crude oil has haigh level of maturity.

Abstract: Starch-based blend membranes is widely us in many application due to their biodegradability and low cost. Starch/Polyvinyl Alcohol/Eggsheell (Starch/PVA/EG) membranes were prepared with turmeric extract as a pH-responsive agent. Turmeric extract has good antioxidant activity and could act as a biosensor that changes color in different pH conditions. This research aims to study the effect of eggshells amount in the blend membranes on its thermal and pH-responsive properties. Starch/PVA/EG sheet was prepared by slip casting method. For pH responsiveness, the sheets were immersed into turmeric extract with 0,5 mg/mL in concentration for 24 hours and dried. Turmeric extract was analyzed using a spectrophotometer UV Visible to observe its response to pH and antioxidant activity. A pH-responsive sheet then analyzed the functional groups, thermal character, and the sheet's response in various pH conditions. A spectrophotometer UV Visible analysis shows that turmeric extract has shifted optimum peak in different pH conditions. An IC50 value of turmeric extract was 14.802 mg/L. Functional groups analysis showed that increasing eggshell addition had shifted peak of carbonyl groups at 1737 cm^-1 to 1627 cm^-1. Presence of CO₃^2- in Starch/PVA/EG sheets were confirmed by peak at 889.18 cm^-1. A DSC analysis results the highest thermal stability was obtained by 50% EG. All the starch/PVA/EG sheets gave response to pH change.

Abstract: There are various approaches to prevent or reduce the transmission of dengue fever, one of which involves interrupting the vector's life cycle through the use of pesticides and biological control methods. Considering the significant impact of synthetic pesticides on the environment, the utilization of natural ingredients such as botanical pesticides is a prudent option. These have minimal to no adverse effects on the environment and are relatively safe for animals and humans. This research aimed to assess the efficacy of a larvicide derived from duku peel extract (Lansium domesticum Correa) against L3 larvae of Aedes sp. It employed a quantitative approach, utilizing an experimental design with a post-test control group. A purposive sampling technique was used to select a total of 600 larvae. The data collected were then analyzed using SPSS version 23. The initial test involved data normalization, with a p-value >0.05 indicating normal distribution of the data. Subsequently, the Pearson correlation test was conducted, revealing a significant correlation with a p-value of 0.000 <0.05. The variables had a strong connection at a Pearson correlation value of 0.998. Probit regression analysis was then performed, yielding results of 4.699 µg/mL for LC50 and 11.234 for LC90 µg/mL.

Abstract: Colorimetry is an analytical method based on the visualization of color changes. This method is simple, inexpensive, and efficient so that it can be applied to detect dissolved ferrous metal ions in the form of Fe (II). Fe (II) ions can form complex compounds with 1,10-phenanthroline ligands in carrageenan matrices of iota and kappa types made in the form of beads. In this study, interference testing and method validation have been conducted to optimize and evaluate beads in the colorimetric detection of Fe (II). The results exhibited that Ni (II) and Cu (II) ions as interferents lowered the color intensity of the complex compound of Fe (II) with 1,10-phenanthroline at concentrations starting from 10 mg/L. Besides, Fe (III) improved the colorimetric detection color intensity from the lowest concentration of 3 mg/L, while Mg (II), at 25 mg/L, decreased the color intensity. Furthermore, the standard curve exposed good linearity. Based on the standard deviation and the standard curve slope, the beads limit in the colorimetric detection of Fe was 0.17 mg/L. The quantification limit obtained through calculations was 0.57 mg/L. The precision could be considered good. The beads interference test for colorimetric detection of Fe (II) had good accuracy with a recovery value of 93-102%. Keywords: Bead, Colorimetric Detection, Validation, Interference Test

Abstract: Heavy metals are hazardous to the environment and living creatures because they cannot be decomposed naturally. Lead is one example of a heavy metal that has a high risk of creating environmental pollution, particularly in water. In this study, the heavy metal lead content was reduced using adsorption with Sulcospira testudinaria shell as a biosorbent. The samples were treated with various conditions, such as without calcination (A), calcination at 500°C (B), and 700°C (C), which were analyzed using FTIR and XRD. Characterization data confirms the presence of functional groups on the material's surface that will interact with lead metal and CaCO₃ decomposition caused by calcination temperature treatment. The adsorption findings of lead metal ions with calcination temperature adjustments showed the best adsorption on the Sulcospira testudinaria shell adsorbent, with an adsorption efficiency (%R) of 97.7% employing material B. This research contributes to reducing solid waste from Sulcospira testudinaria shells while informing the public about how to use shell waste. It can be utilized by the government to address the issue of lead metal pollution in waters.

Abstract: Cr (VI) ion is a heavy metal that can be carcinogenic, so it needs to be reduced by using coconut shell charcoal. The aim of this research is to determine the water content, ash content and iodine content in activated coconut shell charcoal varying the concentration of the NaOH solution 0.5; 1.0; and 2.0 %w/v at the variations temperature of 500; 600; and 700°C and to determine the decrease in Cr (VI) ion levels with activated coconut shell charcoal varying the NaOH solution and temperature, and characterization with Scanning Elecctrone Microscope (SEM). The method for measuring water content, ash using the gravimetric method, measuring iodine content using the yodometric method and Cr content (VI) determined using the visible spectrophotometric method. The research results showed that the quality of coconut shell charcoal activated with variations in NaOH solution has charcoal quality according to SNI No. 06-3730-1995, and the best was activated with NaOH 2 %w/v, 700°C with water content 1.87±0.06%, ash content 5.71±0.02%, and Iodine absorption 1724.10±6.77mg/g. The higher the concentration of NaOH and temperature were the more open the pore morphology, so the ability to adsorb Cr(VI) ions is greater. The higher the carbonation temperature, the percentage reduction in Cr (VI) levels also increases. Conclusion The highest reduction in Cr (VI) levels of 66.66% was obtained by using coconut shell charcoal activated with a 2.0 % b/v NaOH solution with an activation temperature of 700 °C for a soaking time of 120 minutes.

Abstract: This research aims to investigate the potential effect on the performance of Al-Al electrodes in the electrocoagulation method. The influence of this potential can be observed through microplastic removal and turbidity levels. The research was conducted in situ using a chemical beaker, employing Al-Al electrodes at various different potentials (5, 10, 15, and 20 V) that were systematically investigated. The results of this research indicate that an increase in potential has a positive impact on the efficiency of microplastic removal and turbidity levels. Efficiency removal of microplastic and turbidity levels increase with an increase in potential until optimum condition. The microplastic removal efficiency was found to be 100% ± 0 at a potential of 10 V after 60 minutes of electrolysis, with a plate spacing of 2.5 cm and an electrolyte concentration of 0.01 mol/L. At a potential of 10 V, the value of NTU changed from >200 NTU to 30 NTU. This research showed that the effectiveness of the Al-Al electrodes performance is influenced by the potential.

Abstract: This study aimed to classify the various forms of microplastics pollution present in the road dust and soil of Jambi City. We characterized the microplastics using FTIR, SEM-EDS, and binocular microscopy. The microplastics characterization under a microscope yielded forms such as fibers, fragments, and films. Polyethylene (PE), polyvinyl chloride (PVC), and polystyrene (PS) are the most common types of polymers, according to FTIR analysis. SEM-EDS analysis of microplastics elements showed that chlorine, silicon, carbon, aluminium, sodium, and calcium were the most abundant. The majority of the microplastics (MP) had an average maximum diameter of less than 200 µm. The results of the research indicate that polymeric materials from road dust wear off and travel through stormwater, eventually ending up in open waters and larger ecological niches, and are a major source of microplastics pollution.

Abstract: Mineral trioxide aggregate (MTA) is a common biomaterial used for endodontic treatment. However, this material does not have antibacterial activity, and the addition of an antibacterial agent is necessary. In this research, CuO nanoparticles (CuONP) have been added to MTA to improve the compressive strength and antibacterial activity. CuONP was synthesized by mixing 25 mL CuSO₄.5H₂O 0.5 M and Na₂CO₃ 0.5 M at volume variations (15, 25, and 42 mL), sonicating the mixture at a temperature of 60 °C for 2 hours, and calcining at a temperature of 600 °C for 4 hours. MTA/CuO material was made by mixing MTA and CuONP at variations in weight percentage (1, 2, and 3%). CuONP, MTA, and MTA/CuO were characterized with Fourier Transform Infrared (FT-IR), X-ray diffractometer (XRD), and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX). The compressive strength and antibacterial properties against Staphylococcus aureus and Pseudomonas aeruginosa were also tested. The results showed that CuONP was successfully synthesized with an average particle size of 21.94 nm. Adding CuONP 2% to MTA improved its compressive strength of 12.03±0.44 MPa. In addition, the presence of CuONP in the MTA gave the antibacterial property of S. aureus with an inhibition zone value of 6.69±0.67 mm for MTA/CuO-2 and 6.77±0.31 mm for MTA added with 3% of CuONP. However, adding CuONP did not increase significant antibacterial activity against P. Aeruginosa. Adding CuONP 3% increased the inhibition zone from 5.50±00 to 7.04±0.39 mm. The findings indicated that MTA modified with CuONP can potentially be applied for endodontic treatment even though further investigation is still necessary to test the biocompatibility and cytotoxicity.