Biodekolorisasi Metil Oranye Menggunakan Bakteri Ralstonia Pickettii Yang Terimobilisasi Dalam Matriks Pva-Alginat-Hektorit

Asranudin, Asranudin (2023) Biodekolorisasi Metil Oranye Menggunakan Bakteri Ralstonia Pickettii Yang Terimobilisasi Dalam Matriks Pva-Alginat-Hektorit. Doctoral thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penerapan metode biologis pada penanganan limbah pewarna saat ini banyak diterapkan, tidak terkecuali pewarna metil oranye (MO). Degradasi MO seacara biologis diperlukan karena MO termasuk pewarna beracun. Pada penelitian ini biodekolorisasi metil oranye menggunakan bakteri Ralstonia Pickettii yang terimobilisasi dalam matriks pva-alginat-hektorit telah berhasil dilakukan. Penelitian ini diawali dengan sintesis dan modifikasi hektorit menggunakan
cetyltrimethylammonium bromide (CTAB), dan ditemukan bahwa modifikasi hektorit menggunakan CTAB 40% paling optimum meningkatkan karakter materialnya (Hec-40), termasuk kinerja adsorpsi MO. Karekterisasi FTIR, XRD, SEM, TGA-DTG, adsorpsi-desorpsi N2 (setelah kalsinasi) telah menunjukkan CTAB terinterkalasi pada struktur hektorit. Kinerja adsorpsi menggambarkan mekanisme adsorpsi metil oranye mengikuti kinetika orde dua semu, monolayer dan adsorpsi fisik. Dalam bentuk imobilisasi material Hec-40 menjadi BHec-40, kinetika orde satu semu yang paling akurat memprediksi mekanisme adsorpsi MO pada BHec-40, yang terjadi secara monolayer dan secara fisik. Hec-40 selanjutnya dikalsinasi dan dijadikan adsorben pada matriks imobilisasi R. pickettii yang disingkat BHec-RP. Ralstonia pickettii menunjukkan dekolorisasi optimum MO pada kondisi inkubasi statis,
suhu 35-40˚C, pH 7, salinitas 20-40 g/L dan menunjukkan resistensi terhadap ion logam Ni2+, Pb2+, Sr2+, Fe2+, Cu2+ dan Zn2+ pada konsentrasi kurang dari 5mM. Selanjutnya, kinerja dekolorisasi BHec-RP dievaluasi dimana BHec-RP (sel mati) dijadikan kontrol untuk mempeljari mekanisme adsorpsi yang terjadi. Mekanisme adsorpsi yang terjadi pada BHec-RP (PVA-alginat-hektorit-R. pickettii mati) mengikuti kinetika orde satu semu dengan kapasitas adsorpsi optimum 0,6918 mg/g beads. Selain itu, Adsorpsi MO terjadi secara monolayer dan termasuk proses fisik. Selanjutnya, mekanisme dekolorisasi yang dievalusi pada BHec-RP (sel hidup) menunjukkan proses degradasi sesuai dengan kinetika orde satu, dengan laju degradasi tertinggi pada konsentrasi awal MO 50 mg/L (0.025 mg/L/h). Hasil ini menggambarkan bahwa system imobilisasi lebih unggul dalam mendegradasi MO dibandingkan dalam bentuk R. pickettii bebas karena laju degradasi yang lebih rendah yaitu 0,015 mg/L/h. Berikutnya, reaksi dekolorisasi MO menunjukkan peran enzim yaitu azoreduktase, NADH-DCIP reductase dan lakase. Selain itu, R. pickettii
menunjukkan kemampuan degradasi MO dengan menghasilkan lima fragmen molekul yang lebih sederhana yaitu m/z: 267,12; 189,09; 179,07; 169,09 dan 165;05. Dan, optimasi kondisi
dekolorisasi/degradasi berdasarkan variable independent (suhu, pH, waktu inkubasi/dekolorisasi) menggunakan Response Surface Methodology (RSM) dengan melalui design optimasi menggunakan model Box Benkhen Design dengan 15 percobaan, ditemukan kondisi optimum degradasi yakni pada suhu 39,34°C, pH 7,02 dan waktu inkubasi 39,27 menit.
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The application of biological methods in the treatment of dyestuff waste is current widely applied, including methyl orange (MO) dyes. Biological degradation of MO is necessary because MO is a toxic dye. In this study, the biodecolorization of methyl orange using Ralstonia Pickettii immobilized in a pva-alginate-hectorite matrix was
successfully carried out. This research started with the synthesis and modification of hectorite using cetyltrimethylammonium bromide (CTAB), and it was found that the most optimum modification of hectorite using 40% CTAB could improve the character of the material (Hec-40), including MO adsorption performance. Characterization of
FTIR, XRD, SEM, TGA-DTG, N2 adsorption-desorption (after calcination) showed that CTAB is intercalated in the hectorite structure. The adsorption performance describes
the adsorption mechanism of methyl orange following pseudo second order kinetics, monolayer and physical adsorption. In the form of immobilization of Hec-40 material into BHec-40, the pseudo first order kinetics most accurately predicts the MO adsorption mechanism on BHec-40, which occurs in a monolayer and physically. Hec-40 was then calcined and used as an adsorbent on the R. pickettii immobilization matrix, abbreviated as BHec-RP. R. pickettii showed optimum MO decolorization under static incubation conditions, temperature 35-40˚C, pH 7, salinity 20-40 g/L and showed resistance to metal ions Ni2+, Pb2+, Sr2+, Fe2+, Cu2+ and Zn2+ at concentrations less than 5mM. Furthermore, the decolorization performance of BHec-RP was evaluated where BHec�RP (dead cells) was used as a control to study the adsorption mechanism that occurred. The adsorption mechanism that occurs in BHec-RP (PVA-alginate-hektorit-R.pickettii dead cell) follows pseudo first order kinetics with an optimum adsorption capacity of 0.6918 mg/g beads. In addition, MO adsorption occurs in a monolayer manner and includes physical processes. Furthermore, the decolorization mechanism evaluated in BHec-RP (live cell) showed a degradation process according to first order kinetics, with the highest degradation rate at an initial MO concentration of 50 mg/L (0.025 mg/L/h). These results illustrate that the immobilization system is superior in the degradation of MO compared to the free form of R. pickettii because of the lower degradation rate of 0.015 mg/L/h. The MO decolorization reaction shows the role of enzymes namely azoreductase, NADH-DCIP reductase and laccase. In addition, R. pickettii demonstrated the ability to degrade MO by producing five simpler molecular fragments, namely m/z: 267.12; 189.09; 179.07; 169.09 and 165;05. Optimization of ecolorization/degradation conditions based on independent variables (temperature, pH, incubation/decolorization time) using the Response Surface Methodology (RSM) through optimization design using the Box Benkhen Design model with 15 experiments, found the optimum degradation condition at 39.34 °C, pH 7.02 and incubation time 39.27 minutes.

Item Type:	Thesis (Doctoral)
Uncontrolled Keywords:	Ralstonia pickettii, hektorit, CTAB, metil oranye, imobilisasi. Ralstonia pickettii, hectorite, CTAB, methyl-orange, degradation.
Subjects:	Q Science > QD Chemistry > QD251.2 Chemistry, Organic. Biochemistry
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Chemistry > 47001-(S3) PhD Thesis
Depositing User:	Asranudin .
Date Deposited:	31 Jul 2023 03:56
Last Modified:	31 Jul 2023 03:56
URI:	http://repository.its.ac.id/id/eprint/100387

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