Painer Florian, Baldermann Andre, Gallien Florian, Eichinger Stefanie, Steindl Florian, Dohrmann Reiner, Dietzel Martin
Institute of Applied Geosciences & NAWI Graz Geocenter, Graz University of Technology, Rechbauerstraße 12, 8010 Graz, Austria.
Omya GmbH, Gersheimstrasse 1-2, 9722 Gummern, Austria.
Materials (Basel). 2022 Jun 24;15(13):4474. doi: 10.3390/ma15134474.
The hydrothermal alteration of perlite into zeolites was studied using a two-step approach. Firstly, perlite powder was transformed into Na-P1 (GIS) or hydro(xy)sodalite (SOD) zeolites at 100 °C and 24 h using 2 or 5 M NaOH solutions. Secondly, the Si:Al molar ratio of the reacted Si-rich solution was adjusted to 1 by Na-aluminate addition to produce zeolite A (LTA) at 65 or 95 °C and 6 or 24 h at an efficiency of 90 ± 9% for Al and 93 ± 6% for Si conversion. The performance of these zeolites for metal ion removal and water softening applications was assessed by sorption experiments using an artificial waste solution containing 4 mmol/L of metal ions (Me: Ca, Mg, Ba and Zn) and local tap water (2.1 mmol/L Ca and 0.6 mmol/L Mg) at 25 °C. The removal capacity of the LTA-zeolite ranged from 2.69 to 2.86 mmol/g for Me (=240-275 mg/g), which is similar to commercial zeolite A (2.73 mmol/g) and GIS-zeolite (2.69 mmol/g), and significantly higher compared to the perlite powder (0.56 mmol/g) and SOD-zeolite (0.88 mmol/g). The best-performing LTA-zeolite removed 99.8% Ca and 93.4% Mg from tap water. Our results demonstrate the applicability of the LTA-zeolites from perlite for water treatment and softening applications.
采用两步法研究了珍珠岩向沸石的水热蚀变过程。首先，在100℃下用2M或5M的NaOH溶液处理24小时，将珍珠岩粉末转化为Na-P1（GIS）或羟基方钠石（SOD）沸石。其次，通过添加偏铝酸钠将反应后的富硅溶液的Si:Al摩尔比调整为1，在65℃或95℃下反应6或24小时，生成A型沸石（LTA），铝的转化率为90±9%，硅的转化率为93±6%。通过在25℃下使用含有4 mmol/L金属离子（Me：Ca、Mg、Ba和Zn）的人工废水溶液和当地自来水（2.1 mmol/L Ca和0.6 mmol/L Mg）进行吸附实验，评估了这些沸石在金属离子去除和水软化应用方面的性能。LTA沸石对Me的去除容量为2.69至2.86 mmol/g（=240-275 mg/g），与商业A型沸石（2.73 mmol/g）和GIS沸石（2.69 mmol/g）相似，与珍珠岩粉末（0.56 mmol/g）和SOD沸石（0.88 mmol/g）相比显著更高。性能最佳的LTA沸石从自来水中去除了99.8%的Ca和93.4%的Mg。我们的结果证明了由珍珠岩制备的LTA沸石在水处理和软化应用中的适用性。
