MODIFIKASI SILIKA GEL DARI ABU LIMBAH HASIL PROSES PEMBAKARAN INDUSTRI BATU BATA DENGAN DIFENILKARBAZON SEBAGAI ADSORBEN SERTA UJI DAYA SERAP TERHADAP ION LOGAM Cr(III) DAN Cu(II)

The modification of silica gel, from the waste bricks burning process, with diphenylcarbazone has been done. gel modified by (Si-DPZon) was obtained boiling ash NaOH solution to create sodium silicate and neutralized HCl get then physically ligand. study included determination adsorbent functional groups spectrophotometer IR, surface acidity acid-base titration method, specific area absorption methylene blue optimum conditions (pH, contact time) adsorption Cr(III) Cu(II). FTIR analysis showed that Si-DPZon contained amide (N-H), carbonyl (C=O), silanol (Si-OH), siloxane (Si-O-Si) aromatic (C-H) groups. results had a (Kal) 5.8384 ± 0.2466 mmol/g number active sites 12.3945x1020 atom/g 12.6886 m2/g. Si-ABB 4.5568±0,2453 27.4410x1020 11.6712 for chromium (III), both occurred at pH 5 15 minutes. ability time 34.6927 mg/g an percentage 86.7317% 34.5445 86.3611%. Adsorption Cu(II) 26.49672 66.2418% Si- ABB 24.93210 62.3302%.
 Keywords: adsorptions, copper (II), diphenilcarbazone ligand, synthesis gel.