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All Journal CHEMICA Jurnal Teknik Kimia Science and Technology Indonesia IJEMS (Indonesian Journal of Environmental Management and Sustainability) Journal of Integrated and Advanced Engineering (JIAE) Bulletin of Chemical Reaction Engineering & Catalysis
Melwita, Elda
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Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Decision Sciences, Operations Research & Management Electrical & Electronics Engineering Energy Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Physics Public Health

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Removal of Methyl Orange in Aqueous Medium using ZnO/Bentonite as Semiconductor by Photocatalytic Process Priatna, Satria Jaya; Yuliana, Ayu; Zulkarnain; Melwita, Elda; Arsyad, Fitri Suryani; Mohadi, Risfidian
Science and Technology Indonesia Vol. 9 No. 3 (2024): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.3.539-545

Abstract

Pillarization of bentonites (from East Java) with ZnO semiconductors has been synthesized using co-precipitation methods into a ZnO/Bentonite composite and applied as a catalyst in a photocatalytic process to remove Methyl Orange (MO) dyes. The optimum pH condition of MO dyes is at pH 2 with a degradation rate of 22.91% (from 15 mg/L to 11.523 mg/L). The optimum ZnO/Bentonite catalyst weight condition is 200 mg, with a degradation rate of 29.11% (from 15 mg/L to 10.596 mg/L). The optimum time condition for UV lamp irradiation is 60 minutes, with a degradation rate of 64.92% (from 15 mg/L to 5.244 mg/L). The kinetics of MO photocatalytic reaction using ZnO/Bentonite catalyst follows the pseudo-first-order Langmuir Hinshelwood-Santosa kinetic model with photocatalytic reaction rate constant (k1) of 0.014 and photocatalytic equilibrium constant (K) of 0.012.
Enzymatic hydrolysis of cellulose banana stem (alkaline microwave-assisted pre-treatment) Samara, Faras Saskia; Novia, Novia; Melwita, Elda
Journal of Integrated and Advanced Engineering (JIAE) Vol 4, No 1 (2024)
Publisher : Akademisi dan Saintis Indonesia (ASASI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51662/jiae.v4i1.120

Abstract

The banana stem waste holds immense promise as a readily available and abundant source of lignocellulosic biomass, making it a compelling alternative for biofuel and biochemical applications. Therefore, this study focuses on investigating the impact of both time and substrate loading on the enzymatic hydrolysis of banana stem cellulose that has undergone alkaline microwave-assisted pre-treatment. The pre-treatment method involves subjecting the biomass to 5% KOH for 30 min, followed by microwave exposure at 300 W for 5 min, a process aimed at enhancing the accessibility of cellulose. Enzymatic hydrolysis experiments were carried out utilizing cellulase enzymes derived from Aspergillus niger, with variations in hydrolysis times (ranging from 5 to 45 h) and enzyme-to-substrate ratios (ranging from 1:1 to 1:10). The results of this investigation revealed a substantial improvement in hydrolysis efficiency, owing to the synergistic effects of alkaline microwave-assisted pre-treatment, signifying enhanced cellulose accessibility. Notably, the highest concentration of reducing sugars (1.3 mg mL−1) was achieved at a substrate-to-enzyme ratio of 1:1 and a hydrolysis duration of 45 h. These findings provide valuable insights into the conversion of lignocellulosic biomass, emphasizing the potential of integrated pre-treatment strategies for sustainable biorefinery applications. This research contributes to advancing our understanding of lignocellulosic biomass utilization, offering a promising avenue for biofuel and biochemical production from banana stem waste.
Photocatalytic Degradation of Heavy Metals Cd, Cu, Fe and Pb Using ZnO-Zeolite Nanocomposite Ramadhini, Tri Karimah; Agustina, Tuty Emilia; Melwita, Elda; Wijayanti, Maria Siswi
Indonesian Journal of Environmental Management and Sustainability Vol. 7 No. 4 (2023): December
Publisher : Magister Program of Material Science, Graduate School of Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/ijems.2023.7.4.147-152

Abstract

Heavy metals are the main pollutant substances in the environment. Heavy metals are a type of metal with high density and are very dangerous to living organisms, especially humans. Living organisms can adsorb the bioaccumulative and sedimentation of heavy metals that settle in water. Some compounds which found in wastewater including Cadmium (Cd), Copper (Cu), Iron (Fe), and Lead (Pb). These heavy metals cannot naturally degrade, additional processing is required before it being released into the environment. To prevent environmental pollution impacts, wastewater containing heavy metals must be handled properly and optimally. One method that can be applied for wastewater treatment is degradation by photocatalysis, utilizing the assistance of light. This research is to investigate the effect of pH and irradiation time on the degradation of Cd (cadmium), Cu (Copper), Fe (Iron), and Pb (Lead) heavy metals. To enhance the photocatalytic activity, the synthesis of ZnO-Zeolite nanocomposites was conducted. The ZnO-Zeolite nanocomposites produced were analyzed by SEM-EDX and XRD. The utilization of ZnO-Zeolite nanocomposites is deemed effective in reducing heavy metal concentrations. The degradation with Ultraviolet (UV) light exposure runs within 15-120 minutes with pH variation between 4-8. The degradation of heavy metal runs at 60 minutes and 120 minutes showing an optimum percentage removal of metals approaching 100%. The optimum pH values for Cd, Cu, Fe, and Pb are pH 8, pH 7, pH 6, and pH 8, respectively. The sequential metal degradation percentages are 98.96%, 95.43%, 96.07%, and 95.53%, respectively.
Effective Ammonia Removal from Hospital Wastewater by Using a Combination of Filtrations and Bio-Adsorbent from Tea Waste Ariani, Shinta; Nasir, Subriyer; Melwita, Elda
Indonesian Journal of Environmental Management and Sustainability Vol. 8 No. 4 (2024): December
Publisher : Magister Program of Material Science, Graduate School of Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/ijems.2024.8.4.145-153

Abstract

Hospital wastewater contains a high concentration of ammonia that exceed the predetermined quality standards and can cause pollution to the environment. Therefore, the treatment of hospital wastewater is required prior to being released to the environment. Effective ammonia removal process has been developed by using a combination of sponge filtration pretreatment, followed by adsorption using activated carbon from waste of tea leaves, and nanofiltration using ceramic membrane as the final process. Experiment results show the highest effectiveness of ammonia removal of 70% by using filtration only. Effectiveness is increases up to 95% by a combination of filtration and adsorption. A maximum effectiveness of 100% is achieved when using a combination of filtration, adsorption, and nanofiltration. This combination produces an optimal condition for the ammonia removal by using 3 L/min flowrate, adsorbent mass 140 g, and operating time 15 minutes at which the ammonia concentration is 0.08 mg/L. This concentration is below the standard of allowable ammonia concentration of 0.1 mg/L.
CuAl-LDH Modified with Filamentous Macroalgae for Anionic Dyes Removal: A Study on Selectivity, Adsorption Efficiency, and Regeneration Wijaya, Alfan; Hanum, Laila; Melwita, Elda; Lesbani, Aldes
Bulletin of Chemical Reaction Engineering & Catalysis 2024: BCREC Volume 19 Issue 4 Year 2024 (December 2024)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.20223

Abstract

Continuous modifications of Layered Double Hydroxides (LDH) materials are essential to enhance their structural stability and improve their capacity for pollutant adsorption, addressing the need for more effective remediation strategies in environmental applications. This research study has proposed the preparation of CuAl-LDH supported filamentous macroalgae of Spirogyra sp. (CuAl-LDH/SA) via coprecipitation and hydrothermal methods. The prepared CuAl-LDH/SA composites were investigated for the adsorption of direct yellow 12 (DY) and remazol red (RR) dyes in batch mode experiments. The structure and morphology of the prepared CuAl-LDH/SA were identified by X-ray Diffraction (XRD), Fourier Transform Infra Red (FT-IR), (Brunauer-Emmett-Teller) BET surface area, Thermogravimetry / Differential Thermal Analyzer (TG/DTA), and Scanning Electron Microscope (SEM). For the adsorption process, the effects of initial pH, contact time, initial concentration, temperature, adsorption selectivity, and adsorbent regeneration, as well as kinetics, isotherms, and thermodynamics were studied. The adsorption selectivity test resulted in the RR dye being more selective compared to DY. The maximum capacities for RR adsorption were 72.464 mg/g (pH = 2, 150 min, 303 K). CuAl-LDH/SA can be regenerated for 4 cycles with a percent removal of 29.32%. The adsorption process followed the intraparticle diffusion kinetics model and Langmuir isotherm. Thermodynamic studies showed that the adsorption of RR using CuAl-LDH/SA was endothermic and spontaneous. The results of this study indicate that CuAl-LDH/SA composite material shows potential material in the removal of anionic dyes from aqueous solutions. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
Effect of temperature and time on alkaline pretreatment and alkaline microwave-assisted pretreatment on banana stem composition Anggriani, Ulfa Meila; Novia, Novia; Melwita, Elda; Aprianti, Tine
CHEMICA: Jurnal Teknik Kimia Vol. 10 No. 3 (2023): December 2023 [Available online since December 26, 2023]
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26555/chemica.v10i3.27329

Abstract

Banana stem waste is a source of lignocellulose biomass with a high cellulose content and abundant availability in Indonesia. In this work, we investigated the effect of time and temperature on the decrease in rate of lignin in lignocellulose. Banana stem waste was pretreated with alkaline and alkaline microwave-assisted so that the percentage of lignin contained in lignocellulose biomass were reduced and the percentage of cellulose were increased. In alkaline pretreatment, 6% KOH is added to lignocellulose and heated to a hotplate during contact time variation (10, 20, 30, 40, and 50 min) with temperature variations (55, 65, 75, 85, and 95 oC). In pretreatment, an alkaline microwave–assisted 6% KOH solution was added to lignocellulose and heated for 20 min with temperature variations (55, 65, 75, 85, and 95 oC), then was put into a microwave that has a wave power of 360 Hz with variations in contact time (55, 65, 75, 85 and 95 min). After pretreatment, the sample was analyzed using the Chesson method to determine the percentage of cellulose, hemicellulose and lignin. Analysis showed that alkaline and microwave-assisted alkaline pretreatments effectively reduce the lignin percentage and increase the cellulose percentage in lignocellulose. The most remarkable performance in both pretreatments was obtained when working at 95 oC with a contact time of 50 min. Based on process optimization, it was concluded that microwave-assisted alkaline pretreatment reduced the percentage of lignin more and increased the percentage of cellulose compared to alkaline KOH pretreatment, which decreased the rate of lignin by 43.26% and increased the rate of cellulose by 60.68%. For further research, it can be continued to the next process, namely hydrolysis to produce glucose as a raw material for the bioethanol production process.
Co-Authors Aldes Lesbani Anggriani, Ulfa Meila Aprianti, Tine Ariani, Shinta Arsyad, Fitri Suryani Laila Hanum Novia Novia Ramadhini, Tri Karimah Risfidian Mohadi Samara, Faras Saskia Satria Jaya Priatna, Satria Jaya Subriyer Nasir Tuty Emilia Agustina Wijaya, Alfan Wijayanti, Maria Siswi Yuliana, Ayu Zulkarnain