SINTESIS ZSM-23 DARI ABU BATUBARA DAN KINETIKA ADSORPSINYA TERHADAP AMOKSISILIN DALAM LARUTAN

Cemaran amoksisilin di perairan mengalami peningkatan tajam dalam beberapa tahun terakhir. Teknik adsorpsi dipercayai sebagai salah satu cara yang banyak digunakan untuk mengurangi akumulasi antibiotik ini di perairan. Namun, teknik ini memerlukan adsorben yang saat ini harganya semakin mahal, karenanya diperlukan adsorben alternatif yang lebih ekonomis namun berkinerja tinggi. Salah satu strategi yang dapat dilakukan adalah dengan memanfaatkan abu batubara, limbah padat hasil pembakaran batubara. Pada penelitian ini, abu batubara dimanfaatkan sebagai bahan baku untuk preparasi zeolit jenis ZSM, dan pengaruh suhu serta konsentrasi NaOH pada metode hidrotermal dianalisis. Selain itu, kapasitas adsorpsi zeolit sintesis dan kinetika adsorpsinya pada penyisihan obat amoksisilin dalam larutan dipelajari. Zeolit disintesis menggunakan metode hidrotermal dengan variasi perbandingan abu batubara terhadap NaOH (1:1, 1:1,5, dan 1:2) dan variasi suhu (65, 80, dan 95°C). Hasil karakterisasi menunjukkan bahwa zeolit terbaik diperoleh pada perbandingan abu batubara dan NaOH 1:2 pada suhu 95°C. Karakterisasi menggunakan XRD mengkonfirmasi adanya kesesuaian karakteristik zeolit 1:2 dengan ZSM-23. Hasil FTIR menunjukkan adanya pita serapan karakteristik zeolit, yaitu vibrasi Si−O pada bilangan gelombang 999,56 cm-1 dan Al−O pada bilangan gelombang 799,48 cm-1. Hasil karakterisasi SEM-EDS menunjukkan adanya pembentukan morfologi bentuk jarum yang teratur. Berdasarkan hasil analisis BET, luas permukaan spesifik zeolit adalah 433,517 m2/g, meningkat tajam dibandingkan luas permukaan abu batubara. Kapasitas adsorpsi maksimum zeolit pada penyisihan obat amoksisilin (AMX) mencapai 673,5 mg/g. Studi mekanisme adsorpsi dilakukan dengan menguji kesesuaian data hasil adsorpsi menggunakan model isoterm adsorpsi Langmuir dan Freundlich. Hasil analisis menunjukkan bahwa data adsorpsi mengikuti model isoterm Langmuir dengan nilai R2 sebesar 0,9328, dengan demikian interaksi adsorben-adsorbat diduga mengikuti interaksi monolayer. Amoxicillin contamination in waters has increased sharply in recent years. Adsorption technique is believed to be one of the most widely used methods to reduce the accumulation of this antibiotic in waters. However, this technique requires an adsorbent which is currently increasingly expensive, therefore an alternative adsorbent that is more economical but has high performance is needed. One strategy that can be done is to utilize coal ash, solid waste from coal combustion. In this study, coal ash was used as raw material for the preparation of ZSM type zeolite, and the effect of temperature and NaOH concentration on the hydrothermal method was analyzed. In addition, the adsorption capacity of the synthetic zeolite and its adsorption kinetics on the removal of amoxicillin drug in solution were studied. Zeolite was synthesized using the hydrothermal method with variations in the ratio of coal ash to NaOH (1:1, 1:1.5, and 1:2) and temperature variations (65, 80, and 95°C). The characterization results showed that the best zeolite was obtained at the ratio of coal ash and NaOH 1:2 at a temperature of 95°C. Characterization using XRD confirmed the suitability of 1:2 zeolite characteristics with ZSM-23. The FTIR results show the characteristic absorption band of the zeolite, which is the Si−O vibration at a wave number of 999.56 cm-1 and Al−O at a wave number of 799.48 cm-1. The results of SEM-EDS characterization showed the formation of a regular needle shape morphology. Based on the results of BET analysis, the specific surface area of zeolite was 433.517 m2/g, increased sharply compared to the surface area of coal ash. The maximum adsorption capacity of zeolite in amoxicillin (AMX) removal reached 673.5 mg/g. The study of the adsorption mechanism was carried out by testing the suitability of the adsorption data using the Langmuir and Freundlich adsorption isotherm model. The results of the analysis showed that the adsorption data followed the Langmuir isotherm model with an R2 value of 0.9328, therefore the adsorbent-adsorbate interaction was thought to follow the monolayer interaction