TY - JOUR A1 - Hartmann, A. A1 - Petrov, V. A1 - Buhl, J.-C. A1 - Rübner, Katrin A1 - Lindemann, Mathias A1 - Prinz, Carsten A1 - Zimathies, Annett T1 - Zeolite synthesis under insertion of silica rich filtration residues from industrial wastewater reconditioning JF - Advances in chemical engineering and science : ACES N2 - Zeolite synthesis was studied using two silica rich filtration residues (FR 1 and FR 2) as Si-source and sodium aluminate in a direct synthesis at 60°C at strong alkaline conditions (8 M - 16 M NaOH). In addition to these one-pot syntheses, a two-step process was investigated. Here, an alkaline digestion of FR at 60°C was followed by gel precipitation with sodium aluminate and gel crystallization under usual conditions of 80°C - 90°C. The results show that the substitution of chemical reagent sodium silicate by a waste material like FR as Si-source is possible but requires fine tuning of the reaction conditions as zeolite crystallization is a process under kinetic control. The solubility behaviour and impurities of the inserted filtration residues strongly influenced the course of reaction. Thus zeolites like hydrosodalite or intermediate zeolite between cancrinite and sodalite, or zeolite NaA or Z-21 in cocrystallization with hydrosodalite could be observed in the one pot syntheses already in a short time interval between 1 - 4 h depending on the alkalinity. The two step process yield to zeolites NaA and NaX in very good quality. The reaction process of FR in both reaction methods was characterized by chemical analyses, X-ray powder diffraction, Fourier transform infrared spectroscopy as well as scanning electron microscopy. Surface area and water content of selected products were further characterized by the BET-method and by thermogravimetry. Summing up the results, we can show that zeolite formation from filtration residues is possible by several reaction procedures as model cases for a re-use of industrial waste materials. Beside the importance for environmental protection, the reactions are of interest for zeolite chemistry as the re-use of FR is possible under economically conditions of low energy consumption at 60°C and short reaction periods. KW - Zeolites KW - Superalkaline Conditions KW - Filtration Residues KW - Re-Use of Industrial Waste KW - Reaction Kinetics KW - Silica Residue PY - 2014 DO - https://doi.org/10.4236/aces.2014.42015 SN - 2160-0392 SN - 2160-0406 VL - 4 SP - 120 EP - 134 PB - Scientific research publishing CY - Irvine, Calif., USA AN - OPUS4-31840 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -