Handoko Darmokoesoemo
Department Of Chemistry, Faculty Of Science And Technology, Airlangga University Kampus C, Jl. Mulyorejo, Surabaya 60115

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Penentuan Kondisi Optimum Penyerapan Logam Kadmium Oleh Asam Humat Darmokoesoemo, Handoko; Setyawati, Harsasi
Jurnal Matematika dan Ilmu Pengetahuan Alam Vol 17, No 1 (2015)
Publisher : Universitas Airlangga

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Abstract

This research was study on the formation of complexes between metals Cd(II) with humic acid and the optimum conditions of metal Cd(II) adsorption by humic acid. Determination of optimization conditions of metal Cd(II) adsorption by humic acid i.e. variation of contact time, pH and Cd(II) concentration. The results showed the optimum contact time was 90 minutes with a percentage of Cd adsorped was 86.52%, the pH optimum was pH 6 with a percentage of Cd adsorped was 80.39% and the optimum Cd(II) concentration was 500 ppm with the optimum Cd(II) adsorped by humic acid was 221, 8 mg /L. FTIR analysis showed the presence a bond between the metal Cd(II) with oxygen groups of humic acid at wavelength of 354.90 cm-1. The adsorption model of Cd(II) by humic acids showed Langmuir type with correlation coefficient 0,99909.Keywords : humic acid, cadmium, Cd(II)-humat complexes.
APLIKASI CARBOXYMETHYL CHITOSAN - UREA GLUTARAT (CMCHI - UGLU) SEBAGAI KATALIS TERFLUIDAKAN PADA SINTESIS BIODIESEL DARI VIRGIN COCONUT OIL (VCO) Handoko Darmokoesoemo; Suyanto suyanto; Denny Ika Rahmawati
Jurnal Kimia Riset Vol. 1 No. 1 (2016): Juni
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (749.289 KB) | DOI: 10.20473/jkr.v1i1.2439

Abstract

AbstrakPenelitian ini bertujuan untuk mentransformasi kitosan menjadi carboxymethyl chitosanyang selanjutnya diubah menjadi carboxymethyl chitosan urea glutarat (CMChi-UGLU) dan kemudian diaplikasikan sebagai katalis terfluidakan untuk sintesis biodiesel. Selain itu, penelitian ini juga bertujuan untuk menentukan aktivitas katalitik katalis CMChi-UGLU. CMChi-UGLU yang diperoleh dikarakterisasi dengan menggunakan Fourier Transform Infra Red(FTIR) sedangkan biodiesel yang diperoleh dikarakterisasi dengan menggunakan Gas Chromatography-Mass Spectrometry (GC-MS). Sintesis biodiesel dilakukan dengan menggunakan kolom fluidisasi yang diisi denganVirgin Coconut Oil dan metanol (1:60) serta katalis CMChi-UGLU sebanyak 10% b/b minyak selama 90 menit dan pada suhu 65-70°C. Hasil penelitian menunjukkan bahwa aktivitas katalitik katalis CMChi-UGLU adalah 80,046%, hasil ini lebih tinggi dibandingkan katalis chitosan yaitu 40,023%. Kata kunci: kitosan, CMChi-UGLU, fluidisasi, aktivitas katalitik  AbstractThis study aims to transforming chitosan into carboxymethyl chitosan which is converted into carboxymethyl chitosan urea glutaric acid (CMChi-UGLU) that will be used as a fluidized catalyst for synthesis biodiesel. In addition, this study aims to determining the catalytic activity of CMChi-UGLU. CMChi-UGLU is characterized by Fourier Transform Infra-Red(FTIR) while biodiesel is characterized by Gas Chromatography-Mass Spectrometry (GC-MS). Synthesis of biodiesel is performed using fluidization column which filled with virgin coconut oil and methanol (1:60) and also heterogeneous catalyst CMChi-UGLU as many as 10% of oil weight on condition within 90 minutes at temperature 65-70°C. The result of synthesis of biodiesel showed that the catalytic activity of CMChi-UGLU is 80,046%, this result is higher than uses chitosan which it’s catalytic activity is 40,023%. Keywords: chitosan, CMChi-UGLU, fluidization, catalytic activity
Pengembangan Elektroda Pasta Karbon termodifikasi Molecularly Imprinted Polymer sebagai Sensor Potensiometri Asam Urat Mirartul Khasanah; Handoko Darmokoesoemo; Nesti Widayanti
Jurnal Kimia Riset Vol. 1 No. 2 (2016): Desember
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (236.62 KB) | DOI: 10.20473/jkr.v1i2.3085

Abstract

ABSTRAK            Pengembangan elektroda pasta karbon/molecularly imprinted polymer (MIP) sebagai sensor untuk analisis asam urat secara potensiometri telah dilakukan. MIP dibuat dari monomer metil metakrilat, cross-linker etilen glikol dimetakrilat, dan asam urat sebagai template. Elektroda yang memberikan kinerja optimum dibuat dengan komposisi karbon, MIP, dan parafin 40:25:35(%b/b). Pengukuran larutan asam urat dilakukan pada pH optimum 5. Kinerja elektroda dinyatakan dengan nilai faktor Nernst sebesar 30,19 mV/dekade dengan jangkauan pengukuran 10-6-10-3 M, koefisien variasi 1,36-2,03%, akurasi 63,9-166,0 % dan batas deteksi bawah sebesar 3,03x10-6 M. Pengukuran asam urat dengan elektroda ini tidak diganggu oleh keberadaan urea yang ditunjukkan dengan nilai koefisien selektivitas (Kij) kurang dari satu. Elektroda ini memiliki waktu respon kurang dari dua menit dan waktu hidup selama delapan minggu dengan 104 kali pemakaian. Kata kunci: elektroda pasta karbon, MIP, potensiometri, asam urat ABSTRACTCarbon paste electrode modified molecularly imprinted polymer (MIP) as a sensor to analyze uric acid by potentiometry has been developed. MIP was synthesized by mixing methyl methacrylate as monomer, etylene glycol dimethacrylic acid as cross-linker, and uric acid as template. The electrode which showed the best performance was manufactured by ratio of carbon, MIP, and paraffin of 40:25:35 (w/w). The developed electrode showed the optimum performance on the uric acid pH 5. The performances of carbon paste/MIP electrode was expressed by Nernst factor of 30.19 mV/decade, measurement range of 10-6-10-3 M, the coefficient of variation (CV) of 1.36-2.03% and accuracy of 63.9-166.0%. The detection limit of this method was 3.03x10-6 M. Analysis of uric acid using the electrode was not interfered by urea. The developed electrode showed the response time less than 2 minutes, while lifetime of the electrode was 8 weeks (104 times usage). Keyword : carbon paste electrode, MIP, potentiometry, uric acid
KOMPOSISI KIMIA SUBSTRAT ASOSIASI Sonneratia alba - Avicennia marina DI MUARA SUNGAI LEKOK KABUPATEN PASURUAN Hani Sudarmanto; Mas Loegito; Trisnadi Widyoleksono C.P.; Handoko Darmokoesoemo; Sediono
JURNAL PENELITIAN BIOLOGI BERKALA PENELITIAN HAYATI Vol 3 No 2 (1997): December 1997
Publisher : The East Java Biological Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23869/512

Abstract

The mangrove forest occurred in the north coast of Pasuruan Regency have not been reported about the vegetational and substrate compositions. The research's purpose were to analysis the vegetational composition and the chemical properties of the substrate. The result showed that this mangrove forest were dominated by association of Sonneratia alba - Avicennia marina. The result showed that soils had the natural reaction (pH 7.01-7.65), low in organic matter (2.18-4.27%) and total nitrogen (0.48-0.51%), but high in total phosphorus (15.19-29.22 ppm) and in exchangeable cation (Ca2+: 389.855-504.065 mg/100 gr, Mg2+: 409.522-441.400 mg/100 gr, K+: 228.900-390-435 mg/100 gr).