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Sri Redjeki
Department of Chemical Enggineering, Faculty of Engineering, University of Pembangunan Nasional “Veteran” Surabaya, Indone Universitas Pembangunan Nasional “Veteran” Surabaya, East Java, Indonesia
Agriculture, Biological Sciences & Forestry Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Economics, Econometrics & Finance Engineering Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Medicine & Pharmacology

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PEMISAHAN LOGAM MERKURI DENGAN CARA ELEKTRODIALISIS Redjeki, Sri
Jurnal Teknik Kimia Vol 1, No 2 (2007): JURNAL TEKNIK KIMIA
Publisher : Program Studi Teknik Kimia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33005/jurnal_tekkim.v1i2.71

Abstract

Pencemaran merkuri di perairan kebanyakan disebabkan oleh limbah industri, dimanakandungan merkurinya melebihi standar yang telah ditetapkan. Menurut standar Abidin 1997, FDA, danWHO 1990, kadar merkuri yang ditoleransi adalah 15 µg/liter dalam darah, 3.5 µg/liter dalam ASI, 1 ppmdalam ikan dan makanan, 2 ppm dalam kuku, dan 4 ppm dalam urine, (Rahem, 2004), 2 hingga 7 ppmpada rambut. Normalnya, kadar merkuri dalam tubuh adalah dibawah 0.1 ppm. Dan seharusnya, nilaiambang batas untuk merkuri di perairan hanya 0.005 ppm. (http:/www.pdpersi.co.id).Limbah merkuri yang dibuang inilah yang lebih berbahaya, sebab setelah menjadi limbahdan merkuri tersebut masuk ke perairan, maka merkuri dengan mudah berikatan dengan klor dalam airlaut. Ikatan dengan klor yang disebut merkuri inorganik itu akan mudah masuk kedalam plankton dandapat berpindah ke biota laut lain, lalu akan tertransformasi menjadi merkuri organik (metil merkuri),yang dalam bentuk inilah merkuri lebih mudah diserap oleh tubuh. (http:/www.jawapos.co.id)Teknologi pemisahan dengan membran sendiri telah membuat kemajuan yang pesat dalamtahun-tahun belakangan ini. Proses elektrodialisis menghilangkan ion-ion dari air dengan mendorongnyamelewati membran dengan arus DC. Teknologi ini dipilih karena biayanya yang murah, pemakaian energiyang rendah, sederhana, dan ramah lingkungan, tidak memerlukan bahan-bahan tambahan sepertipengekstrak, juga tidak memerlukan energi (panas), yang juga sangat sensitif terhadap produk-produktertentu.Dengan pengurangan konsentrasi ( % konversi) yang cukup besar, yaitu 88.5197 % tersebut, makamodul Elektrodialisis mampu mengurangi konsentrasi diluat dengan cukup baik. Untuk konsentrasi umpan10 ppm, 20ppm, 30 ppm, dan 40 ppm, konversi terbesar adalah pada 12 Volt, dengan keberhasilanpengurangan konsentrasi diluat hingga sebesar 88.5197 % yaitu pada konsentrasi umpan 40 ppm.Kata Kunci : Mecuri, elektrodialisis
ALTERNATIVE ENERGY BIOGAS FROM CHOCOLATE PEEL Mardhita Arlindawati, Sri redjeki, Dias Asmoro Putra,
Jurnal Teknik Kimia Vol 6, No 1 (2011): JURNAL TEKNIK KIMIA
Publisher : Program Studi Teknik Kimia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33005/jurnal_tekkim.v6i1.81

Abstract

The development of alternative energy fuel technology at present many are produced from biologicalresources, eg the manufacture of biodiesel and biodiesel as a fuel substitute for gasoline. This aims to obtainbiogas that can be used as alternative energy and find operating conditions that produce appropriate levelsof CH4 in the standard Indonesian. The first stage is done by preparing 1 liter of raw materials ie brown rindand water are then mixed with a starter (cow dung) 10% of the volume of raw materials and the addition ofyeast and grass after it is mixed until blended. Then put into containers / bottles that have been fitted hose,water manometer, and the gas holder. The research was done in stages with the conditions that you run.Variables that run is a comparison of raw material (1:1; 1:1.5; 1:2; 1.5:1; 2:1), observation time (5 days, 10days, 15 days, 20 days, 25 days , 30 days), and the variable addition of grass (50 gr, 100 gr, 150 gr, 200 gr).From the results of this study found the greatest level of 74.22% in comparison 1 (water): 1.5 (brown skin)with the addition of 150 g of grass while low levels of 60.04% in comparison 2 (water): 1 (brown skin ) withthe addition of 200 g of grass, the results of this study meets the National Standards of Indonesia.Key words: Biogas, grass, yeast
KINETIKA FERMENTASI VCO SECARA SINAMBUNG DALAM BIOREAKTOR TANGKI IDEAL Redjeki, Sri; Kurniati, Ely
Jurnal Teknik Kimia Vol 8, No 1 (2013): JURNAL TEKNIK KIMIA
Publisher : Program Studi Teknik Kimia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33005/jurnal_tekkim.v8i1.711

Abstract

Tujuan dari penelitian ini adalah merumuskan kinetika reaksi pada proses fermentasi sinambung, pada pembuatan VCO. Fermentasi sinambung dijalankan dengan mengalirkan substrat dengan laju aliran tertentu dan pada saat yang sama produk hasil metabolisme dikeluarkan dengan laju alir yang sama. Penambahan medium baru dengan laju yang sesuai dapat menghasilkan keadaan tunak (steady state), pada keadaan tunak tersebut konsentrasi sel, laju pertumbuhan, konsentrasi produk tidak mengalami perubahan selama waktu fermentasi berlangsung. Penentuan parameter Yp/s, vp, km’ dapat ditentukan dari berbagai percobaan laju pengenceran. Hasil yang diperoleh adalah untuk nisbah (1:2): vp= 0,06 jam-1, km’ = 4,0451 g/l, dan Yp/s = 6 g asam laktat/g glukosa.
Pengelolaan Genangan Air Dangkal untuk Meningkatkan Hasil Padi dengan Kerangka Kerja System of Rice Intensification (SRI) Maftukhah, Rizki; Erni R, -; Purwanto, Benito Heru; Sri R, -; Arif, Sigit Supadmo
Jurnal Irigasi Vol 10, No 1 (2015): Jurnal Irigasi
Publisher : Balai Teknik Irigasi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (599.313 KB) | DOI: 10.31028/ji.v10.i1.41-48

Abstract

Nowadays, the issues of water scarcity, high fertilizer cost, and negative environmental impacts due to high agrochemicals use are escalating so that the improvement of resource efficiency on rice cultivation is necessary. Based on many studies, SRI is a very promising approach. Pot experiment was conducted under SRI framework with continuous flooding (CF), shallow water depth (SWD), and field capacity (FC) irrigation; together with four different doses of organic fertilizer (F100, F50, F0, and LF). The aim of this study is to figure out the effect of water and organic fertilizer managements on rice performances. Our experiment showed soil Eh was significantly different between three water management treatments (p < 0.05) where FC gained the highest soil Eh, followed by SWD and CF. Whereas, organic fertilizer management gave insignificant effect on soil EH. Under SWD management, number of tillers was significantly higher than CF and FC. On the other hand, water management and organic fertilization had no significant effect on plant height. SWD significantly increased yield and biomass followed by CF and FC. Organic fertilizer caused significant reduction on number of tiller, yield and biomass. In conclusion, SWD provided better environment for rice growth and enhance the rice performances, while the effect of organic fertilizer was not clearly seen.
GARAM SEHAT RENDAH NATRIUM MENGGUNAKAN METODE BASAH Redjeki, Sri; Muchtadi, Dimas Faizal Akbar; Putra, Muhamad Reza Arief
Jurnal Teknik Kimia Vol 14, No 2 (2020): JURNAL TEKNIK KIMIA
Publisher : Program Studi Teknik Kimia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33005/jurnal_tekkim.v14i2.2040

Abstract

Garam konsumsi (NaCl) merupakan kebutuhan yang sangat penting bagi manusia, diantaranya sebagai bumbu dan pengawet makanan. Selama ini kebanyakan orang mengonsumsi makanan hanya memikirkan selera dan rasanya saja sehingga kurang memperhatikan apa yang dibutuhkan oleh tubuh. Hipertensi adalah salah satu permasalahan dalam tubuh, karena peningkatan tekanan darah sistolik dan diastolik. Sebenarnya, garam konsumsi yang dijual bukanlah penyebab dari meningkatnya tekanan darah. Namun, kandungan natrium di dalam garam itulah yang menyebabkan hipertensi. Garam sehat diharapkan dapat menurunkan tekanan darah bagi penderita hipertensi yang memiliki kadar maksimum natrium sebesar 60% berat dan kadar kalium maksimum sebesar 40% berat. Pada penelitian ini akan dibuat garam rendah Natrium dengan penambahan Kalium Klorida (KCl) sebagai bahan campuran. Kadar Natrium dalam garam konsumsi nantinya akan menurun dengan penambahaan kalium klorida, penambahan dilakukan dengan perbandingan massa NaCl dan KCl 1:3, 1:2, 1:1, 2:1, 3:1 dari total massa bahan yang nantinya setiap bahan akan dilarutkan dan diaduk menjadi satu dengan suhu pengadukan 40°C, 70°C, 100°C. Diaduk hingga terjadi proses rekristalisasi. Perbandingan yang paling baik dalam percobaan ini,  untuk mendekati garam dengan kadar NaCl 60% dan KCl 40%, yaitu pada perbandingan massa NaCl dan KCl 1:1 pada suhu 70°C. Kata kunci : garam konsumsi ; garam sehat ; hipertensi ; kalium klorida ; natrium klorida. DOI : https://doi.org/10.33005/jurnal_tekkim.v14i2.2040
Increase the Sugar Concentration of the Solution Sugar by Reverse Osmotic Membrane Sri Redjeki; Nur Hapsari; Iriani
Nusantara Science and Technology Proceedings International Seminar of Research Month Science and Technology in Publication, Implementation and Co
Publisher : Future Science

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

Abstract

Sugar is one of the basic needs of people and food and drink industry. As technology advances and the demand for efficient usage of sugar rises, crystal sugar is seen as less advantageous than liquid sugar. If sugar is always dissolved in water before use, then it will be more efficient and practical for consumers to use sugar in liquid form than in crystal form. Other than that, liquid sugar is also attractive to consumers because it is economical, hygienic, instantly soluble in hot and cold water, fresher and longer-lasting, able to thicken and enrich the texture of foods and drinks, and functions as sweetener, syrup, and flavor enhancer. Liquid sugar is also more beneficial for sugar producers because of simpler production process, cheaper production cost, and similar yield with no extra cost. In sugar production, separation process is found in most of its stages and therefore the use of membrane technology for separating solute and water content has a good potential. In this research, water content reduction of sugar solution was done in order to increase the sugar concentration of the solution. The parameters of this research were 4%, 5%, and 6% starting concentration of sugar solution; 20, 40, and 60 minutes of process time; and 85 and 60 PSI ?P. The best result was acquired on 4% starting concentration, 60 PSI ?P, and 60 minutes process time.
Co-Authors Benito Heru Purwanto Erni Romansyah Iriani Kurniati, Ely Maftukhah, Rizki Muchtadi, Dimas Faizal Akbar Nur Hapsari Putra, Muhamad Reza Arief SIGIT SUPADMO ARIF