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Kinetic Study of Subcritical Water Extraction of Carbohydrate from Microalgae Nannochloropsis sp. Nur Baiti Listyaningrum; Muhammad Mufti Azis; Sarto Sarto; Anis Nurdhiani Rosdi; Mohd Razif Harun
ASEAN Journal of Chemical Engineering Vol 21, No 1 (2021)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ajche.60015

Abstract

Microalgae contain a significant amount of carbohydrates that can be converted further to produce valuable compounds. To extract carbohydrates from microalgae, sub-critical water extraction (SWE) is a viable and novel method. Compared to other existing chemical and biological extraction methods, SWE is more economical, effective, and efficient in terms of process conditions. This process uses high temperature and pressure of water at just below supercritical conditions to keep water at a liquid state. This study aims to investigate the factors that affect the extraction yield of carbohydrates from microalgae Nannochloropsis sp. using the SWE process. The extraction was carried out at a temperature of 160 – 320 oC, a duration of 5 – 25 min, and microalgal biomass loading of 5 - 25% w/v. The kinetics study was conducted in an extraction time of 5 – 25 min at 200 oC and 5% (w/v) biomass loading. A simplified kinetic model based on a consecutive reaction was used to describe carbohydrate production and decomposition via SWE. It was found that the maximum yield of total carbohydrate was 18.04 g/100 g which was obtained at 200 oC, 10 min, and 5% (w/v) microalgal biomass loading. The carbohydrate concentration was decreased as the temperature, extraction time and microalgal biomass loading increased. This result indicated that the SWE is a promising extraction method for carbohydrate recovery from microalgae, and the factors investigated here had a significant effect on the extraction process. The proposed kinetic model was also able to capture the experimental data well within the range of operating conditions studied in this work. 
KAJIAN PENGARUH LAPISAN MEDIA PADA NON-VEGETATED SWALE SEBAGAI FILTER LARUTAN PUPUK NPK Rizki Zulapriansyah; INTAN SUPRABA; Muhammad Mufti Azis
Jurnal Sains & Teknologi Lingkungan Vol. 14 No. 2 (2022): SAINS & TEKNOLOGI LINGKUNGAN
Publisher : Teknik Lingkungan Universitas Islam Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Penggunaan pupuk NPK pada lahan pertanian secara berlebihan mengakibatkan banyak pupuk tidak terserap sehingga terbawa masuk ke perairan oleh limpasan air permukaan saat hujan dan menyebabkan eutrofikasi. Unsur hara anorganik Nitrogen (N) dan Fosfor (P) menjadi nutrisi bagi alga sehingga menyebabkan tumbuhnya alga yang berlebihan pada perairan atau biasa disebut algal bloom. Penelitian ini bertujuan untuk mengkaji seberapa besar pengaruh jenis dan tinggi lapisan media pada non-vegetated swale dalam menyaring parameter Nitrogen (N) dan Fosfor (P) yang berasal dari larutan pupuk NPK komersial. Metode yang diterapkan adalah dengan menyiramkan aliran air larutan pupuk NPK melalui non-vegetated swale dengan dua ketebalan lapisan yang berbeda. Konsentrasi masuk larutan NPK yaitu 123,77-124,77 mg/l fosfat, 16,54-16,72 mg/l amoniak serta kandungan nitrat dan nitrit yang kecil. Aliran air larutan pupuk NPK sebelum dan sesudah melalui non-vegetated swale diambil sampelnya yang kemudian diuji dengan alat spektrofotometer untuk mengetahui perbedaan kandungan fosfat, nitrat, nitrit dan amonianya. Hasil penelitian menunjukkan bahwa kedua non-vegetated swale memiliki kemampuan menyaring konsentrasi fosfat pada larutan air pupuk NPK yang sangat baik, kedua non-vegetated swale mampu mengurangi sekitar 120 mg/l konsentrasi fosfat. Hasil pengukuran nitrat dan nitrit menunjukkan kenaikan sekitar 5 mg/l nitrit dan nitrat, sedangkan kandungan amoniak turun sekitar 16 mg/l. Hal ini menunjukkan terjadinya proses nitrifikasi dan menunjukkan bahwa kedua non-vegetated swale pada penelitian ini memiliki kemampuan penyaringan N yang belum optimal.
Analisis perubahan sistem kualitas udara Kota Yogyakarta pada masa pandemi COVID-19 Himawan Novianto; Muhammad Mufti Azis; Hilya Mudrika Arini
Jurnal Rekayasa Proses Vol 16, No 2 (2022)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.71888

Abstract

Beberapa penelitian membahas penurunan konsentrasi polutan udara selama masa pandemi COVID-19, namun belum banyak penelitian yang membahas kaitan antara variabel kualitas udara dan tingkat mobilitas masyarakat. Penelitian ini menyelidiki keterkaitan hubungan antara variabel polutan udara, faktor meteorologi, dan tingkat mobilitas masyarakat di Kota Yogyakarta. Fenomena hubungan sistem kualitas udara dan mobilitas masa pandemi COVID-19 tahun 2020 terbagi dalam dua periode: (a) Pembatasan Aktivitas (April s.d. Juli 2020) dan (b) Normal Baru (Agustus s.d. Desember 2020). Kualitas udara Kota Yogyakarta sebelum dan pada masa pandemi COVID-19 menunjukkan perbaikan, dari kategori Baik: 31,85% menjadi 90,37% ISPU (chi-square asymp.  sig.  < 0,05).   Polutan udara PM10, SO2, dan CO menurun sebesar 18%, 93%, dan 74%, sedangkan O3 meningkat sebesar 104% pada masa pandemi COVID-19 tahun 2020. Polutan udara primer PM10, SO2, dan CO berhubungan positif terhadap faktor meteorologi penyinaran matahari, tetapi berhubungan negatif terhadap polutan udara sekunder O3 serta faktor meteorologi suhu udara, kelembaban udara, curah hujan, dan kecepatan angin. Pembatasan aktivitas masyarakat di luar rumah secara umum menyebabkan perbaikan kualitas udara, di mana penurunan mobilitas transportasi menjadi variabel yang mempengaruhi penurunan polutan udara primer di Kota Yogyakarta. Pembatasan aktivitas mempengaruhi polutan udara sekunder, di mana kenaikan O3 terjadi ketika mobilitas dalam ruangan dan transportasi meningkat.
Kinetic Modeling of C3H6 Inhibition on NO Oxidation over Pt Catalyst Muhammad Mufti Azis; Derek Creaser
Bulletin of Chemical Reaction Engineering & Catalysis 2016: BCREC Volume 11 Issue 1 Year 2016 (April 2016)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.11.1.412.27-33

Abstract

Exhaust after treatment for lean burn and diesel engine is a complex catalytic system that consists of a number of catalytic units. Pt/Al2O3 is often used as a model Diesel Oxidation Catalyst (DOC) that plays an important role to facilitate oxidation of NO to NO2. In the present study, we proposed a detailed kinetic model of NO oxidation as well as low temperature C3H6 inhibition to simulate temperature-programmed reaction (TPR) data for NO oxidation over Pt/Al2O3. A steady-state microkinetic model based on Langmuir-Hinshelwood mechanism for NO oxidation was proposed. In addition, low temperature C3H6 inhibition was proposed as a result of site blocking as well as surface nitrite consumption. The model can explain the experimental data well over the studied temperature range. 
Experimental and Kinetic Modeling of Galactose Valorization to Levulinic Acid Retno Ringgani; Muhammad Mufti Azis; Rochmadi Rochmadi; Arief Budiman
Bulletin of Chemical Reaction Engineering & Catalysis 2022: BCREC Volume 17 Issue 2 Year 2022 (June 2022)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.17.2.14032.451-465

Abstract

Levulinic acid, a versatile chemical building block, was derived from C6-sugar galactose using sulfuric acid as the catalyst. Galactose is monosaccharide of polysaccharides constituent that is mostly contained in third generation biomass, macro-microalgae. It currently receives high attention to be a source of renewable feedstock. The effect of temperature, catalyst concentration and initial substrate loadings were studied for 60 min, in the temperature range of 150–190 °C, acid concentration of 0.25–0.75 M and initial substrate loading of 0.05–0.25 M. The highest levulinic acid yield of 40.08 wt% was achieved under the following conditions: 0.05 M galactose, 0.75 M acid concentration, 170 °C temperature, and 40 min reaction time. The kinetic model was developed by first order pseudo-irreversible reaction. The results showed that the proposed model could capture the experimental data well. These results suggested that galactose, derived from macro- and micro-algae, can potentially be converted and applied for platform chemicals. Copyright © 2022 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).