Biochar Dari Tandan Kosong Kelapa Sawit Termodifikasi Cangkang Tiram Sebagai Adsorben Fosfat

Buana, Galuh Ayu Kartika (2026) Biochar Dari Tandan Kosong Kelapa Sawit Termodifikasi Cangkang Tiram Sebagai Adsorben Fosfat. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kelebihan fosfat di perairan berpotensi memicu eutrofikasi, sehingga diperlukan teknologi pengolahan yang efektif. Penelitian ini bertujuan untuk mempelajari pengaruh modifikasi kalsium berbasis cangkang tiram terhadap karakteristik fisikokimia biochar tandan kosong kelapa sawit (TKKS) hasil pirolisis suhu tinggi serta mengevaluasi kinerjanya dalam mengadsorpsi fosfat dan mekanisme adsorpsi yang terlibat. Biochar TKKS disintesis melalui pirolisis pada suhu 800 °C dengan yield rata-rata 42%, kemudian dimodifikasi secara pasca-pirolisis menggunakan larutan kalsium dari cangkang tiram dengan variasi rasio massa biochar–kalsium. Uji adsorpsi fosfat dilakukan secara batch meliputi pengaruh pH, waktu kontak, konsentrasi awal, dan keberadaan ion pengganggu. Kondisi optimum adsorpsi diperoleh pada pH 8 untuk sampel BC-0,5 dengan kapasitas adsorpsi sebesar 15,161 mg/g, meningkat signifikan dibandingkan biochar tanpa modifikasi (BC-0) sebesar 5,946 mg/g pada pH yang sama. Studi kinetika menunjukkan bahwa adsorpsi fosfat pada BC-0,5 paling sesuai mengikuti model pseudo-second-order (R² = 0,999; Qe,cal = 15,848 mg/g) yang mengindikasikan bahwa laju adsorpsi dikendalikan oleh interaksi kimia pada permukaan adsorben. Kapasitas maksimum eksperimen kinetika mencapai 17,532 mg/g pada waktu kontak 1440 menit. Peningkatan konsentrasi awal fosfat hingga 200 mg/L meningkatkan kapasitas adsorpsi maksimum eksperimen menjadi 20,922 mg/g. Pemodelan isoterm adsorpsi menunjukkan kesesuaian terbaik pada model Freundlich (R² = 0,976; 1/n = 0,818) yang menandakan adsorpsi berlangsung secara favorable pada permukaan heterogen, sedangkan model Langmuir memberikan estimasi kapasitas monolayer teoritis sebesar 37,879 mg/g. Uji ion pengganggu menunjukkan bahwa kapasitas adsorpsi BC-0,5 tetap berada pada kisaran ±14,337–15,928 mg/g dalam sistem multikomponen, dengan ion SO₄²⁻ memberikan penghambatan paling signifikan. Hasil karakterisasi menunjukkan keterlibatan kalsium sebagai situs aktif pengikatan fosfat, yang ditunjukkan oleh kandungan Ca sebesar ±2,0 wt% pada BC-0,5 yang menurun menjadi ±1,1 wt% setelah adsorpsi serta terdeteksinya fosfor sebesar ±0,3 wt%. Analisis XRD dan FTIR mengindikasikan keterlibatan spesies kalsium dalam pembentukan interaksi Ca–P, sedangkan analisis adsorpsi–desorpsi isotermal N₂ menunjukkan perubahan sifat pori dengan luas permukaan spesifik berturut-turut sebesar 191,014 m²/g (BC-0), 45,399 m²/g (BC-0,5) dan 112,575 m²/g (BC-0,5+P). Diameter pori BJH berada pada kisaran 3,393 –3,411 nm, menunjukkan dominasi mesopori yang juga tercermin dari adanya loop histeresis. Secara keseluruhan, hasil penelitian ini menunjukkan bahwa modifikasi kalsium berbasis cangkang tiram efektif meningkatkan kinerja adsorpsi fosfat pada biochar TKKS.
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Excessive phosphate in aquatic environments can trigger eutrophication, highlighting the need for effective treatment technologies. This study aims to investigate the effect of oyster shell–based calcium modification on the physicochemical characteristics of oil palm empty fruit bunch (OPEFB) biochar produced via high-temperature pyrolysis, as well as to evaluate its phosphate adsorption performance and the associated adsorption mechanisms. OPEFB biochar was synthesized by pyrolysis at 800 °C with an average yield of 42%, followed by post-pyrolysis modification using a calcium solution derived from oyster shells with varying biochar-to-calcium mass ratios. Batch adsorption experiments were conducted to examine the effects of pH, contact time, initial phosphate concentration, and the presence of competing ions. The optimum adsorption condition was achieved at pH 8 for the BC-0.5 sample, yielding an adsorption capacity of 15,161 mg/g, which was significantly higher than that of unmodified biochar (BC-0), which showed a capacity of 5,946 mg/g under the same conditions. Kinetic analysis revealed that phosphate adsorption onto BC-0.5 followed the pseudo-second-order model most closely (R² = 0,999; Qe,cal = 15,848 mg/g), indicating that the adsorption rate was governed by chemical interactions at the adsorbent surface. The maximum experimental adsorption capacity from kinetic studies reached 17,532 mg/g at a contact time of 1440 min. Increasing the initial phosphate concentration up to 200 mg/L further enhanced the maximum experimental adsorption capacity to 20,922 mg/g. Adsorption isotherm modeling showed the best fit with the Freundlich model (R² = 0,976; 1/n = 0,818), suggesting favorable adsorption on a heterogeneous surface, while the Langmuir model provided a theoretical monolayer adsorption capacity of 37,879 mg/g. Interference ion tests demonstrated that the adsorption capacity of BC-0.5 remained within ±14,337–15,928 mg/g in a multicomponent system, with SO₄²⁻ exhibiting the most pronounced inhibitory effect. Characterization results confirmed the involvement of calcium as active sites for phosphate binding, as indicated by a Ca content of approximately 2.0 wt% in BC-0.5, which decreased to about 1.1 wt% after adsorption, along with the detection of phosphorus at approximately 0.3 wt%. XRD and FTIR analyses suggested the participation of calcium species in Ca–P interactions. Nitrogen adsorption–desorption analysis revealed changes in pore properties, with specific surface areas of 191.014 m²/g (BC-0) 45,399 m²/g (BC-0.5) and 112.575 m²/g (BC-0.5+P). The BJH pore diameters ranged from 3,393 –3,411 nm, indicating mesopore contributions also reflected by the presence of hysteresis loops. Overall, this study demonstrates that oyster shell–based calcium modification effectively enhances the phosphate adsorption performance of OPEFB biochar.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Adsorpsi fosfat, Biochar TKKS, Modifikasi Cangkang Tiram, Isoterm Freundlich, Kinetika pseudo-second-order, Phosphate adsorption, OPEFB biochar, Oyster shell modified, Freundlich isotherm, Pseudo-second-order model
Subjects:	Q Science > QD Chemistry > QD117 Absorption Q Science > QD Chemistry > QD281 Pyrolysis Q Science > QD Chemistry > QD75.2 Chemistry, Analytic T Technology > TD Environmental technology. Sanitary engineering > TD195.B56 Biomass energy
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Chemistry
Depositing User:	Galuh Ayu Kartika Buana
Date Deposited:	03 Feb 2026 01:16
Last Modified:	03 Feb 2026 01:16
URI:	http://repository.its.ac.id/id/eprint/131715

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