Corrosion Activity of Carbon Steel B450C and Low Chromium Ferritic Stainless Steel 430 in Chloride-Containing Cement Extract Solution

The carbon steel B450C and low chromium SS 430 ferritic samples were exposed for 30 days to chloride-containing (5 g L−1 NaCL) cement extract solution. The initial pH ≈ 13.88 decreased to pH ≈ 9.6, associated mainly with the consumption of OH− ions and the formation of γ-FeOOH, α-FeOOH, Fe3O4 and Cr(OH)3, as suggested by XRD and XPS analysis, in the presence of CaCO3 and NaCl crystals. The deep corrosion damages on B450C were observed around particles of Cu and S as local cathodes, while the first pitting events on the SS 430 surface appeared after 30 days of exposure. The change in the activity of each type of steel was provided by the potentiodynamic polarization curves (PDP). Two equivalent electrical circuits (EC) were proposed for quantitative analysis of EIS (Nyquist and Bode diagrams). The calculated polarization resistance (Rp), as an indicator of the stability of passive films, indicated that SS 430 presented relatively constant values, being two-three orders of magnitude higher than those of the carbon steel B450C. The calculated thickness (d) of the SS 430 passive layers was ≈0.5 nm and, in contrast, that of the B450C passive layers tends to disappear after 30 days.

Limbah Sabut Kelapa Muda (Cocos nucifera L.) sebagai Sumber Pewarna Kain

Young coconut coir (Cocos nucifera Linn.) waste has the potential to be processed into a useful product, namely as a source of natural dyes, especially in cotton fabrics. Processing is carried out through a maceration process for 72 hours using 96% ethanol as solvent. The obtained extract was applied on cotton cloth with various concentrations of the extract solution, 5, 10, 15, 20, and 25%, and various soaking times of the fabric in the extract for 60, 90, 120, 150, and 180 minutes. The extract was analyzed using Uv-Vis Spekctrofotometer it showed that the ethanol extract or dye that is absorbed into the cotton fabric with various concentrations is 3.43, 4.82, 6.61, 7.79, and 9.03%, respectively. The various soaking times show that on the other hand that the extract absorbed into the fabric was successfully obtained around 7.75, 9.64, 10.81, 11.65, and 12.04%. The results show that the concentration of the extract solution and the increasing length of soaking time can increase the percentage of extract or dye absorbed in cotton fabrics

Antioxidants Activity of Self-Nanoemulsifying Drug Delivery System on Dayak Onions Extract (Eleutherine palmifolia) using DPPH (2,2 difenil-1- picrylhydrazyl) Method

Dayak onions (Eleutherine palmifolia L. Merr) is one plant that has been proven to have benefits as an antioxidant. The Dayak extract is formulated in the self nano emulsifying drug delivery system (SNEDDS) because the extract has low water solubility. The aims this study to develop the SNEDDS formulation system by testing its antioxidant activity. We determined whether there was an increase in antioxidant activity when formulated in the form of SNEDDS or not. The results were then compared with a solution of Dayak onions extract without using SNEDDS. The obtained formula was the optimal result that has been done before using the D-optimal mixture design method. The results of the components consisted of 50 mg of Dayak extract, 10 % caprylic triglyceride as oil, 1% tween 80, and 6,60 % transcutol as a combination surfactant and 12,40 % propylene glycol as co-surfactant. Antioxidant activity testing was carried out using the DPPH (1,1-Diphenyl-2-picrylhydrazyl) method. The antioxidant test using the DPPH method was done with two samples, namely the extract solution and Dayak onion extract SNEDDS. We elaborated the research by using UV-VIS spectrophotometer. Each sample was made into five concentrations, namely 30 ppm, 60 ppm, 90 ppm, 120 ppm, and 150 ppm, and carried out three times replications. The results showed that the IC50 value in the Dayak onion extract solution was 227,19 ppm (very low), while for the SNEDDS solution for the Dayak onion extract the IC50 value obtained was 38,97 ppm (very strong). The analysis was carried out next using an independent T-Test to obtain the results. There was no significant difference between the extract solution and the SNEDDS solution of Dayak onion extract.

Extracting, evaluating biological activities of phenolic compounds from yellow onion peels (Allium cepa L.) and their applicability for fish preservation

The research aimed to evaluate total phenolic content extracted from onion (Allium cepa L.) peels and some of the extract biological activities. The potential of the extract for preserving fish was also investigated. Onion peel extracted with EtOH 60% at 60°C (60 minutes, solid/liquid ratio 1g/20ml) yielded highest polyphenol content 168.49 ± 0.02 GAE/g DW and flavonoid content (216.43 ± 0.06 mg QE/g DW). The extract showed potent antioxidant property in DPPH radical scavenging assay with IC50 value of 12.48 ± 0.45 μ/mL and good antibacterial activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Salmonella, Pseudomonas aeruginosa with MIC values of 175; 175: 200; 200: 150 (μ/mL) respectively. The extract also displayed alpha-glucosidase inhibition activity with IC50 value of 142.53 μg/mL and negligible tyrosinase inhibition activity. Measurement of the PV, TBARS values of basa catfish fillets coated with the extract solution at different concentrations, it was observed that fish samples treated with 3% extract solution could greatly reduce the lipid oxidation under 4°C and -18°C storage conditions compared with untreated samples. The PV, TBARS values after 4 weeks were comparable to 200ppm BHT treated samples.

THE ENHANCED PHOTOCATALYTIC PROPERTIES OF SILVER PHOSPHATE SYNTHESIZED UNDER MANGOSTEEN PEEL EXTRACT SOLUTION

The synthesis of silver phosphate (Ag3PO4) photocatalyst has been widely developed for organic pollutant degradation. However, the large particle of this photocatalyst limits the photocatalytic activity. The smaller particle size of the Ag3PO4 photocatalyst was successfully prepared using the starting material of AgNO3 and Na2HPO4.12H2O under mangosteen peel extract solution. The starting materials were dissolved in mangosteen peel extract solutions prepared at the concentration of 1% (w/v). The reaction of silver nitrate and phosphate solution was conducted at room temperature. The samples of pristine Ag3PO4 and Ag3PO4 prepared under mangosteen peel extract were studied using XRD, DRS, SEM, BET, and FTIR. All photocatalytic activities were evaluated using Rhodamine B photooxidation under blue light irradiation (LED, 3 Watt). The results showed that the mangosteen peel extract significantly decreased the particle size, lowered the bandgap energy from 2.12 to 2.00 eV, and increased the crystallinity of Ag3PO4. The interaction of xanthones from mangosteen peel extract solution with silver ion might affect the growth particle of Ag3PO4, and inhibit the agglomeration leading to small particle size, more uniform distribution, high crystallinity, and low bandgap energy. These properties enhanced the photocatalytic activity up to 2.9 times higher compared to the sample without the treatment of mangosteen peel extract.

Studies on the Separation and Purification of the Caulis sinomenii Extract Solution Using Microfiltration and Ultrafiltration

The separation and purification process of alkaloids faces great challenges of pollution, high energy consumption and low continuity. In this study, the effects of ceramic microfiltration (MF) membrane (membrane pore size of 0.50 μm, 0.20 μm, 0.05 μm) and organic ultrafiltration (UF) membrane (membrane molecular weight cut-off of 10 KDa and 1 KDa) on the separation and purification of Caulis sinomenii extract solution in pilot scale were studied. The cleaning effects of different cleaning methods (pure water, 1% HCl-NaOH, 1% sodium hypochlorite) were investigated. The experimental results indicated that 0.05 μm ceramic membrane and 1 kDa UF membrane have higher sinomenine hydrochloride (SH) permeabilities and total solids (TS) removal rates. The ceramic membrane was circulating cleaned by 1% sodium hypochlorite solution for 1 h; the membrane flux can be restored to more than 90% of the original, the membrane flux of 1 kDa UF membrane can be restored to 99.2% of the original by pure water washing. From the above study, the optimal technic parameters was determined in which 0.05 μm ceramic MF membrane and 1 kDa UF membrane were used to separate and purify the Caulis sinomenii extract solution to remove the invalid ingredients, and the two kinds of membranes were cleaned with 1% sodium hypochlorite solution and pure water, respectively, to keep satisfactory membrane fluxes. The study provided an environment-friendly alternative for the separation and purification of alkaloids in natural products, which has a good prospect for the industrial application.

SURFACE ROUGHNESS IMPROVEMENT OF POLYAMIDE RESIN DENTURE AFTER SOAKING IN 50% CINNAMON (Cinnamon burmanii) SOLUTION

Polyamide resin is widely used in dentistry as a denture base material. Cinnamon burmanii has been proven to have antibacterial and antifungal substances. Therefore, it is the potential to be used as a nature denture cleanser. This study aimed to examine the effect of soaking 50% cinnamon extract solution on the surface roughness of polyamide resin. This study used 16 polyamide resin samples soaked in 50% cinnamon extract solution and 16 samples soaked in distilled water as the control group. It examined the surface roughness before and after immersion for four days and seven days. Data were analyzed using paired T-test and independent T-test. The results showed a significant difference in the surface roughness of polyamide resin before and after immersion in cinnamon solution for four days and seven days. The surface roughness change is due to the polyphenol's reaction on the polyamide resin surface, which has destroyed the polymer chain of polyamide resin.