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All Journal The Journal of Pure and Applied Chemistry Research Jurnal Penelitian Pendidikan IPA (JPPIPA)
Diah Mardiana
Brawijaya University
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Education Materials Science & Nanotechnology Medicine & Pharmacology Physics

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Acid Isolation Techniques for Silica isolation from Rice Husk and Determination of Its Physicochemical Properties Siti Mutrofin; Leo Krisna; Diah Mardiana; Rachmat Triandi T
The Journal of Pure and Applied Chemistry Research Vol 11, No 1 (2022): Edition January-April 2022
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2022.011.01.641

Abstract

Previous research showed that rice husk has a high silica content so it becomes an alternative for processing rice waste. The acid leaching method is a technique to isolate silica by adding an acid solution. The research aim is to obtain the optimum silica yield and determine the chemical ash content of rice husks (rice IR-64,). Rice husks were first calcined at two various temperatures and times. The average yields obtained were 19.54% (500oC / 1 hr), 18.42% (500oC / 2 hrs), 25.03% (700oC /1 hr), and 22.4% (700oC/2 hrs). The physical appearance of ash was grains and white (700 oC/1hr), that were rinsed with 1 M HCl solution to remove impurities. Added 1 M NaOH was to form sodium silicate. The last step was to isolate silica using different concentrations of HCl and HNO3 (3 M, 2 M, and 1 M). The highest result was 99.87% of silica under HNO3 1 M solution. An infrared study supports that the isolated product was silica, with the presence of prominent peaks at 1102 cm-1 (stretching Si-O) and 471 cm-1 (bending Si-O). A unique peak at 958 cm-1 for Si-O-Ca present at the isolated silica using HCl 3 M, gives information on inosilicate type structure. X-ray diffraction analysis with QualX application showed that silica had cristobalite and wollastonite peaks, and the value of crystallinity index was about 63.91%.
The Development of Diazinon Sensors using Polyvinyl Alcohol (PVA) Membrane CuO on Surface Screen-Printed Carbon Electrode (SPCE) as a Receptor Anisa Resti; Ani Mulyasuryani; Diah Mardiana
The Journal of Pure and Applied Chemistry Research Vol 8, No 2 (2019): Edition May-August 2019
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2019.008.02.468

Abstract

The development of Diazinon sensor has been studied using polyvinyl alcohol (PVA-CuO membrane on the surface of the screen-printed carbon electrode (SPCE) as a receptor. The membrane used consisted of polyvinyl alcohol (PVA) 5% (w/v), citric acid 5% (w/v), glutaraldehyde 4% (v/v), Diazinon solution 40 ppm (v/v), and CuO 5% (w/v). This study established the effect of Diazinon at 0.01,0.02 and 0.03 (w/w). besides, the concentration of CuO was 0.5 and 1 (w/w). Signal measurements were carried out in the concentration range of the Diazinon 10-12 - 10-5 M solution in Britton-Robinson buffer at pH 2 - 5. Besides, the influence of the electrolyte type was studied using HCl pH 4, 10-5 M KCl, pH 3 phosphate, and phosphate-KCl pH 3 buffers. The results of the Diazinon sensor characterization showed that the highest sensitivity was obtained at 42 mV/decade with a response time of 180 seconds.
Koefisien Difusi Ion Fosfat dalam Gel Asam Sitrat-Agarosa yang Digunakan dalam Gradien Difusif pada Sampler Pasif Film Tipis (DGT) Digwanggi Arum Tazkiyatu An-Nufuus; Barlah Rumhayati; Qonitah Fardiyah; Diah Mardiana; Ulfa Andayani; Layta Dinira
Jurnal Penelitian Pendidikan IPA Vol 9 No 8 (2023): August
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v9i8.3593

Abstract

In this research, the diffusion coefficient of phosphate ions in agarose-citric acid diffusive gel has been studied. The agarose-citric acid diffusion layer was prepared by mixing 1.5% agarose solution with the addition of citric acid solutions at various concentration. The diffusive gel was casted between two glass plates which were separated using a spacer of 0.1 cm thickness and clamped together in the three sides. Gel was formed for 15 minutes in an oven at 40oC. The diffusion coefficient then was calculated using Fick's First law formula. Gel that produced with addition of 0.45% citric acid absorbed more water during immersion in water for 3 hours for facilitating phosphate diffusion. Swelling degree of the agarose citric acid diffusive gels was not affected by the storing solution condition either in water or in NaNO3 0.1 M. Coefficient diffusion of phosphate in the agarose-citric acid diffusive gel was 1.009×10-7 cm2s-1, less than the diffusion in the pure agarose gel 1.367×10-7 cm2s-1. The diffusion is affected by the ionic strength of solution. Phosphate diffusion coefficient is higher in the phosphate solution with addition of 2 mgL-1 nitrate. Increasing the ionic strength causes lower phosphate diffusion coefficient because the electrostatic attractive and repulsive force
Co-Authors Ani Mulyasuryani Anisa Resti Barlah Rumhayati Digwanggi Arum Tazkiyatu An-Nufuus Layta Dinira Leo Krisna Qonitah Fardiyah Rachmat Triandi T Siti Mutrofin Ulfa Andayani