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Comparative Study of Various Kinetic Models on Leaching of NCA Cathode Material Soraya Ulfa Muzayanha; Cornelius Satria Yudha; Luthfi Mufidatul Hasanah; Linggar Tungga Gupita; Hendri Widiyandari; Agus Purwanto
Indonesian Journal of Chemistry Vol 20, No 6 (2020)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.49412

Abstract

The kinetics study of NCA leaching in the HCl system was proposed. Various kinetic models such as shrinking core, logarithmic rate law, and Avrami equation were used to find out the most appropriate kinetic models for this process. The effect of HCl concentrations, leaching temperatures, solid to liquid (S/L) ratio, and leaching duration were observed. The optimum conditions of NCA leaching were at HCl concentration of 4 M, temperature of 80 °C, S/L ratio of 100 g/L, and leaching time of 1 h. The result shows that shrinking core model with diffusion control process of residue layer describes well the leaching mechanism in this research, which is indicated by the good fitting of coefficient values of correlation (R2) and confirmed by the activation energy values of Ni, Co, Al that were less than 40 kJ/mol.
Identifikasi dan Kuantifikasi Antosianin dari Fraksi Bunga Rosela (Hibiscus Sabdariffa L) dan Pemanfaatannya sebagai Zat Warna Dye-Sensitized Solar Cell (DSSC) Mitha Dea Anggistia; Hendri Widiyandari; Khairul Anam
Jurnal Kimia Sains dan Aplikasi Vol 19, No 2 (2016): Volume 19 Issue 2 Year 2016
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (886.472 KB) | DOI: 10.14710/jksa.19.2.50-57

Abstract

Identifikasi antosianin dari fraksi bunga Rosela (Hibiscus Sabdariffa L.) dan pemanfaatannya sebagai zat warna dye-sensitized solar cell (DSSC) telah dilakukan. Penelitian ini bertujuan untuk mengkuantifikasi kadar antosianin dari fraksi bunga rosela dan menentukan hubungan kadar antosianin terhadap efisiensi sel pada DSSC. Metode yang digunakan adalah (i) ekstraksi antosianin dengan maserasi, (ii) fraksinasi ekstrak antosianin secara kromatografi kolom dengan fasa gerak air-metanol (100:0, 75:25, 50:50, 25:75, 0:100) dan fasa diam sephadex LH-20, (iii) identifikasi senyawa antosianin dengan KLT dan penampak bercak (AlCl3 dan uap amoniak), (iv) kuantifikasi kadar antosianin, (v)  aplikasi zat warna antosianin ke DSSC dan (vi) karakterisasi senyawa antosianin pada fraksi yang memiliki performansi DSSC paling tinggi menggunakan spektroskopi UV-Vis dan IR. Hasil penelitian menunjukan kadar relatif antosianin mempengaruhi nilai efisiensi sel surya DSSC. Semakin besar kadar relatif antosianin maka nilai efisiensi sel surya semakin tinggi. Fraksi 1 menunjukkan nilai kadar relatif antosianin 3,56% dan nilai efisiensi sel surya yaitu 1,014 x 10-4%, sedangkan fraksi 2 menunjukkan nilai kadar relatif antosianin 40,29% dan nilai efisiensi sel surya fraksi 2 yaitu 6,59 x 10-4 %.
Pest Control on Shallots Using Solar-Powered Trap Lights in Srimulyo Village, Sragen Regency Hendri Widiyandari; Yofentina Iriani; Kusumandari Kusumandari; Fahru Nurosyid; Khairuddin Khairuddin; Risa Suryana
ABDIMAS: Jurnal Pengabdian Masyarakat Vol. 6 No. 1 (2023): ABDIMAS UMTAS: Jurnal Pengabdian Kepada Masyarakat
Publisher : LPPM Universitas Muhammadiyah Tasikmalaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35568/abdimas.v6i1.2821

Abstract

Shallots one of a leading vegetable commodity in Central Java. However, the shallot farming industry is frequently confronted with the issue of decreasing yields due to the presence of plant pests. Onion plant pests include the butterfly (Spodoptera exigua) and the leafminer fly (liriomyza). There are two approaches to dealing with this pest problem: pesticides/insecticides and light traps. In terms of organic farming methods, the use of light traps is more profitable. However, the operational costs are quite high because farmers must have a generator to generate electricity, diesel fuel to turn on the generator, oil to lubricate the engine, operators, or must connect to the PLN electricity network. So, we used a solar-powered pest trap lamp system with Li-ion batteries as the energy storage medium to solve this problem. In Srimulyo village, Gondang district, Sragen regency, community service activities such as installing pest trap lights to control pests on shallots were carried out. The onion farmer group association is the service activity's partner (Gapoktan). This activity was well received by shallot farmers because the presence of this light trap can reduce pest attacks.
Hydrazine and Urea Fueled-Solution Combustion Method for Bi2O3 Synthesis: Characterization of Physicochemical Properties and Photocatalytic Activity Yayuk Astuti; Prisca Putri Elesta; Didik Setyo Widodo; Hendri Widiyandari; Ratna Balgis
Bulletin of Chemical Reaction Engineering & Catalysis 2020: BCREC Volume 15 Issue 1 Year 2020 (April 2020)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.15.1.5483.104-111

Abstract

Bismuth oxide synthesis using solution combustion method fuelled by hydrazine and urea has been conducted. This study aims to examine the effect of the applied fuels, urea and hydrazine, on product characteristics and photocatalytic activity in degrading rhodamine B dye. Bismuth oxide synthesis was initiated by dissolving bismuth nitrate pentahydrate (Bi(NO3)3.5H2O) in a nitric acid solvent. Fuel was added and then stirred. The solution formed was heated at 300 ºC for 8 hours. The product obtained was then calcined at 700 ºC for 4 hours. Bismuth oxide synthesized with urea (BO1) and hydrazine (BO2) as fuels both obtained form of yellow powder. The formation of bismuth oxide is indicated by the vibrations of the Bi–O–Bi and Bi–O groups and the crystal structure of a-Bi2O3 in both products. Photocatalytic activity test showed that BO1 has a photocatalyst activity in degrading rhodamine B higher than that of BO2 with constant values of  3.83×10-5 s-1 and 3.43×10-5 s-1, respectively. The high photocatalytic activity can be examined through several factors, such as: band gap values, crystal structure, morphology, and surface area, acquired as a result of the use of different fuels in the synthesis process. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
Ag-TiO2 for Efficient Methylene Blue Photodegradation Under Visible Light Irradiation Widiyandari, Hendri; Nashir, Muhammad; Parasdila, Hanaiyah; Almas, Khanza Fadhilah; Suryana, Risa
Bulletin of Chemical Reaction Engineering & Catalysis 2023: BCREC Volume 18 Issue 4 Year 2023 (December 2023)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.19885

Abstract

Photocatalysis is one of the environmentally friendly methods for degrading down wastewater contamination. TiO2 as one of the photocatalyst material is claimed can enhance the photocatalytic activity much better, if the band gap energy is reduced. In order to reduce the bandgap energy of TiO2, the novel in this research is that the temperature variations over a 24-hour period at 100 °C, 120 °C, 140 °C, and 160 °C in hydrothermal process to synthesize the photocatalyst material with Ag-doped. Diffraction patterns of Ag-TiO2 show that all sample have tetragonal crystal structure and an anatase phase which also has excellent crystallinity. Some of the nanoparticles on the surface of Ag-TiO2 have a consistent morphology, while other particles are formed irregularly. According to the DRS UV-Vis result, bandgap energy reduced as temperature increased (Eg = 3.2 eV to 2.32 eV). The results from PL Ag-TiO2 160 have the lowest intensity, which indicates a low rate of electron-hole recombination. The Ag-TiO2 160 sample produced the best photocatalytic activity, according to the results of the MB degradation test, with a relative change in concentration of 92.98% for 2 h under visible light. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 
Pengembangan Energi Alternatif Biogas dari Sampah Organik di Desa Wonorejo Polokarto Sukoharjo Kusumandari Kusumandari; Risa Suryana; Yofentina Iriani; Fahru Nurosyid; Hendri Widiyandari; Khairuddin Khairuddin; Mohtar Yunianto; Mokhamad Sahid Praptomo
SEMAR (Jurnal Ilmu Pengetahuan, Teknologi, dan Seni bagi Masyarakat) Vol 14, No 1 (2025): Mei
Publisher : LPPM UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/semar.v14i1.94019

Abstract

Permasalahan sampah di Indonesia menjadi perhatian serius pemerintah. Berbagai usaha pengelolaan sampah dilakukan untuk mengurangi penumpukan sampah. Salah satunya dengan pengelolaan sampah jenis organik menjadi sumber energi alternatif yaitu biogas. Dalam rangka kegiatan pengabdian kepada masyarakat, dilakukan pengolahan sampah organik menjadi energi alternatif Biogas. Kegiatan pengabdian dilakukan di Desa Wonorejo Polokarto Sukoharjo. Desa Wonorejo terdiri atas beberapa dukuh dengan total penduduk berjumlah 5783 orang. Selain rumah penduduk, di desa Wonorejo juga terdapat beberapa institusi Pendidikan mulai dari SD sampai SMA dan juga pondok pesantren dibawah Muhammadiyah. Oleh karenanya wilayah desa Wonorejo termasuk wilayah yang padat penduduk dengan beban sampah yang dihasilkan per hari yang cukup banyak. Sampah tersebut terdiri atas sampah organik dan non organik. Untuk sampah non organik warga dapat mengumpulkannya dan menjual ke pengepul sampah non organik. Tetapi untuk sampah organik, penduduk masih menghadapi kendala karena belum dapat mengolahnya menjadi sesuatu yang lebih bermanfaat. Oleh karenanya pengolahan limbah organik menjadi biogas menjadi salah satu alternatif untuk mengatasi masalah tersebut. Pengolahan dimulai dengan pembuatan biodigester sebagai reaktor tempat terbentuknya gas, kemudian pengisian dengan starter dan uji fungsional. Dari pengabdian ini diharapkan masyarakat mendapatkan kemanfaatan teknologi tepat guna untuk menunjang kehidupan dalam usaha pengelolaan sampah khususnya sampah organik.