SINTESIS DAN KARAKTERISASI SILIKA XEROGEL DARI ABU KULIT JAGUNG (ZEA MAYS L.) MELALUI METODE SOL-GEL SERTA APLIKASINYA PADA ADSORPSI DAN DESORPSI KRISTAL VIOLETNIM.: 22106030059Annisa Isniyatur RohmahauthorXerogel silica from corn husk ash (Zea mays L.) has been synthesized through the sol-gel method and used as an adsorbent for crystal violet dye. This study aims to synthesize and characterize the silica xerogel using FTIR, XRD, and BET, examine the effects of pH, contact time, and initial concentration of crystal violet on adsorption capacity, and evaluate the desorption capability of crystal violet from the silica xerogel after the adsorption process. The synthesis was conducted by extracting silica from corn husk ash using 2M NaOH, forming a hydrogel with 1M HCl until pH 7, and then drying it to obtain silica xerogel. Characterization was performed using FTIR to identify functional groups, XRD to determine structure, and BET to analyze surface and pore characteristics. FTIR characterization results indicated the presence of silanol (Si–OH) and siloxane (Si–O–Si) groups, while XRD showed an amorphous silica structure with a broad peak at 2θ around 22–24°. BET analysis revealed a specific surface area of 336.457 m²/g, total pore volume of 0.688 cm³/g, and an average pore diameter of 7.693 nm, indicating mesoporous material characteristics. Adsorption test results showed optimal conditions at pH 7 with an adsorption efficiency of 93.5%, optimal contact time of 20 minutes with efficiency of 95.74%, and optimal initial concentration of 30 ppm with efficiency of 95.46% and adsorption capacity of 28.253 mg/g. Kinetic analysis indicated that the adsorption process was more consistent with a pseudo-second-order model with an R² value of one, while isotherm analysis showed higher conformity to the Freundlich model (R² = 0.8190). Desorption using HCl at concentrations of 0.5; 1; and 2 M resulted in desorption percentages of 1.50%; 0.64%; and 0.49%, respectively, indicating that crystal violet can only be released in small amounts from the silica xerogel.543 Kimia Analitikal, Kimia Analisis2026-08-19UIN SUNAN KALIJAGA YOGYAKARTA;FAKULTAS SAINS DAN TEKNOLOGIThesis