Materials Science Forum Vol. 967

Abstract: Physical factor for chitinase production by Trichoderma virens was first carried out using screening factor of 2-level factorial. The design was employed by selecting incubation time, temperature, moisture substrate, pH, inoculums size and concentration ammonium sulphate as a model factors. The result of 2-level factorial design experiment showed thal all three independent variable have significant effect on chitinase production. The physical factor was further optimized using Central Composite Design in which response surface was generated later from the derived model. An experimental design of three variables including various incubation time, temperature and moisture substrate were created using Design Expert® Software, Version 6.0.4 The design consist of 20 experiments, which include 6 replicate at center points. The optimal value for each variable are incubation time sixth days, temperature 27.83°C and moisture substrate 54% with predicted chitinase activity of 0.48738 U/g of dry substrate. These predicted parameters were tested in the laboratory and the final chitinase activity obtained was 0.48864 U/g of dry substrate, which is similar to the predicted value. The obtained value of the chitinase production was 0.48738 U/g IDS, which was 1.2 fold higher than that of the 2-level factorial design (0.261 U/gds)

Abstract: In recent years, the development of efficient green chemistry methods for synthesis of metal nanoparticles has become a major focus of researchers. One of the most considered methods is production of metal nanoparticles using plants. In this study silver nanoparticles (AgNPs) were rapidly synthesized by reacting silver ions with Moringa oleifera L. leaf extract. The reaction process was simple and convenient to handle, and was monitored using ultraviolet-visible (UV-Vis) spectrophotometer. The crystalline phase of the AgNPs was determined from X-Ray Diffraction (XRD) patterns. The UV-vis spectra gave surface plasmon resonance for synthesized AgNPs at 465-473 nm. The XRD analysis showed that AgNPs are crystalline in nature and have face centered-cubic geometry with average particle size of 32 nm.

Abstract: The use of heterogeneous catalysts in the biodiesel production process provides advantages because it is easier in the catalyst separation process. One type of heterogeneous catalyst that can be used is CaO. The raw materials for CaO are abundant in nature and can be obtained from various sources including agricultural waste such as eggshells. The alkalinity level of CaO can be increased to super baser CaO through the activation process of CaO by using an ammonium carbonate solution. Super base CaO which is used as a catalyst for transesterification reaction in the production of biodiesel made from palm oil. This research was carried out by varying the reaction time starting from 1, 2 and 3 hours. The highest yield was obtained at 3 hours reaction time of 93.92%. The results of the analysis of the physical properties of biodiesel obtained density in the range 853-854 kg/m3, kinematic viscosity 3.24-3.26 mm2/s (cSt), saponification number 193-201 mg-KOH/g biodiesel and acid number 0.3-0.7 mg-KOH/g. These characteristics meet the biodiesel quality standards based on Indonesian National Standard (SNI) 04-7182-2015. Thus the use of super base CaO from eggshells can be used as a catalyst in the process of biodiesel production.

Abstract: A research has been conducted to activate natural zeolites from Mamasa, West Sulawesi with sulfuric acid and heating which is then used as a catalyst for cracking palm oil methyl esters. This type of research is preliminary research. The acidification process is carried out by mixing fine natural zeolites with 0.2 N H2SO4 solution, accompanied by heating at 110 °C. Then zeolite is calcined at 600 °C for 3 hours. The result of zeolite X-Ray diffraction (XRD) analysis shows that Mamasa natural zeolite has mordenite. The crystallinity of natural zeolites is 60.8%, increasing to 68.6% after activation. Catalytic cracking is carried out by heating methyl esters (biodiesel) and active zeolite zeolite catalysts in a fixed bed reactor in several temperature variations (140, 160, and 180 °C), reaction time of 5 minutes. The results of the saponification number analysis show that cracking products have a greater saponification number (224.4 mg KOH/g oil) compared to biodiesel before cracking (220.2 mg KOH/g oil), so it is assumed that the carbon cracking carbon chain is shorter.

Abstract: Silver nanoparticles act as anti-bacterial and anti-inflammatory. On the other hand, some plants contain reducing agents. Therefore, it is deemed necessary to know the potentiality of plant extracts such as green tea leaf extract on the synthesis of silver nanoparticles. The Methanol extract of green tea leaves serves as a reduction of AgNO₃ solution. Determination of the optimum reaction time in forming nanosize using UV-Vis spectrophotometer every 30 minutes. Characterization of nanoparticles obtained using scanning electron microscopy (SEM) and particle size analyzer (PSA). The results showed that green tea leaf extract was able to reduce Ag ⁺ to silver nanoparticles at a reaction time of 90 minutes, the temperature of 70°C. Morphology is not uniform, tends to aggregate, and the size distribution of silver nanoparticles is 82.33-740.89 nm with an average diameter of 157.8 nm.

Abstract: An ion chromatographic method for determination of bromide and bromate in the presence of standard anions in drinking water was described. The method was based on separation on Metrosep A Supp 7-250 (250 x 4 mm) column with 3.6 mmol/L Na₂CO₃ as eluent and conductivity detection after sequential chemical and carbon dioxide suppression. The influence of flow rate and column temperature was studied and optimal experimental conditions for simultaneous determination of eight anions were chosen. Analytical characteristics of the ion chromatographic method were assessed for simultaneous determination of bromide, bromate, fluoride, chloride, nitrate, nitrite, phosphate and sulfate. The calibration curves were linear (r²=1, N=7) in the concentration ranges: 0.4-12 mg/L BrO₃^- and 0.3-11 mg/L Br^-. Recovery test was performed on a spiked certified reference material for soft drinking water. The obtained recoveries for bromate and bromide were 96.0 and 101.0 %, respectively. The repeatability and intermediate precision were between 5.1 and 0.14 % (RSD) depending on the analytes concentration. The limits of detection were 20 μg/L BrO₃^- and 10 μg/L Br^-

Abstract: Pharmaceuticals and personal care products (PPCPs) in the environment have been intensively studied recently. These compounds can cause serious problem in environment. Intake of these compounds in low concentration can threat human health due to its reactivity and chemical composition. Occurrences of PPCPs in environments are important to recognize in order to draw broad understanding on which mitigation of PPCPs can be deliberated. This review provides general information about occurrence of PPCPs. Moreover, sources of PPCPs in the environment are comprehensively explained. The fate and transport mechanisms of PPCPs are summarized based on important studies of selected groups of PPCPs which conducted through years based on several previous study cases are mentioned and elaborated to pinpoint the existence of these pollutants. In the end, identification of the current research limitation and further recommendations are proposed for improving mitigation process and addressing further research.

Abstract: Availability of raw water is one of the problems faced in the provision of clean water services in Indonesia. The purpose of this study was to determine differences in the quality of ordinary well water and drill water with physical parameters test. The number of samples in this study was 12 drill wells and 12 ordinary wells belonging to residents in the City of Parepare and the total were 12 villages. The parameters observed refer to the Indonesian Minister of Health Regulation Number 479 / Menkes / Per / IV / 2010 concerning Water Quality Requirements and Supervision which includes physical parameters such as turbidity. Data collection methods used in this study were cross sectional analysis in South Sulawesi Provincial Health Laboratory Makassar. Based on the results of the laboratory test for measuring water quality as measured by one of the physical parameters, namely turbidity, there is a difference in value between ordinary wells and boreholes. The turbidity values ​​measured in ordinary wells are 3 villages that do not meet the requirements of clean water quality, where all of the results are above the maximum set level of> 5 NTU, the villages is watang Soreang village, Lompoe village and Galung Maloang village while the turbidity value is measured in drill wells are the result that meets the requirements of clean water quality where the results do not exceed the maximum set level of 5 NTU.

Abstract: This study aims to determine the content of n-alkanes in the sediment around the coast of Makassar using the MOPI (Marine Oil Pollution Index) indicator. The method includes the sediment sampling from nine different stations with the Phleger Corer Sampler in gravimetric analysis to identify the concentration of organic material extract and aliphatic fraction. To identify the characteristic of n-alkane hydrocarbons, gas chromatography of mass spectra method was applied. The results of the aliphatic fraction (F1) analysis of the coastal sediments which were contaminated with low biogenic - petrogenic have a MOPI scores of 3, which is supported by a high UCM (Unresolved Complex Mixture) and n-alkane identified between C₁-C₄₄. While the sediments that come from natural processes, pure - biogenic and biogenic, have MOPI scores ​​between 1 and 2. This is supported by the chromatogram profile with an area of ​​UCM generally smaller by n-alkanes identified between C₁₅-C₅₈

Abstract: This paper presents the effect of nanosilica (NS) on compressive strength and microstructure of cement paste containing high volume slag and high volume slag-fly ash blend as partial replacement of ordinary Portland cement (OPC). Results show that high volume slag (HVS) cement paste containing 60% slag exhibited about 4% higher compressive strength than control cement paste, while the HVS cement paste containing 70% slag maintained the similar compressive strength to control cement paste. However, about 9% and 37% reduction in compressive strength in HVS cement pastes is observed due to use of 80% and 90% slag, respectively. The high volume slag-fly ash (HVSFA) cement pastes containing total slag and fly ash content of 60% exhibited about 5%-16% higher compressive strength than control cement paste. However, significant reduction in compressive strength is observed in higher slag-fly ash blends with increasing in fly ash contents. Results also show that the addition of 1-4% NS improves the compressive strength of HVS cement paste containing 70% slag by about 9-24%. However, at higher slag contents of 80% and 90% this improvement is even higher e.g. 11-29% and 17-41%, respectively. The NS addition also improves the compressive strength by about 1-59% and 5-21% in high volume slag-fly ash cement pastes containing 21% fly ash+49%slag and 24% fly ash+56%slag, respectively. The thermogravimetric analysis (TGA) results confirm the reduction of calcium hydroxide (CH) in HVS/HVSFA pastes containing NS indicating the formation of additional calcium silicate hydrate (CSH) gels in the system. By combining slag, fly ash and NS in high volumes e.g. 70-80%, the carbon footprint of cement paste is reduced by 66-76% while maintains the similar compressive strength of control cement paste. Keywords: high volume slag, nanosilica, compressive strength, TGA, high volume slag-fly ash blend, CO₂ emission.