Catalfamo Paola, Primerano Patrizia, Arrigo Ileana, Corigliano Francesco
Dipartimento di Chimica Industriale e Ingegneria dei Materiali, Università di Messina, Italia.
Ann Chim. 2006 Jul-Aug;96(7-8):487-92. doi: 10.1002/adic.200690049.
The extraction of silica from powdered glass cullet with an aqueous solution of sodium hydroxide has been proposed as an alternative to glass recycling aimed to the low temperature production of sodium silicates. The unextracted residue obtained after a counter current two-step extractive process at approximately 100 degrees C and room pressure is mainly made of calcium and sodium silicate and shows high porosity and a large surface area. We thought that it could be active as an agent for the removal of heavy metals from wastewater. In this paper the capacity of the unextracted residue of removing six metal ions (i.e., Cu2+, Ni2+, Zn2+, Cd2+, Pb2+ e Cr3+) was studied in a stirred batch reactor. The data obtained demonstrate that the removal of metal ions from wastewater is achieved with high capacity in a short time and their concentration is lowered under the legal limits without any appreciable influence from changes of physical and chemical conditions. Sodium and calcium ions take the place of heavy metals in water while pH keeps almost neutral. The exchange mechanism was identified.
有人提出用氢氧化钠水溶液从碎玻璃粉中提取二氧化硅，作为玻璃回收利用的一种替代方法，旨在低温生产硅酸钠。在约100℃和常压下进行逆流两步萃取过程后得到的未萃取残渣主要由硅酸钙和硅酸钠组成，具有高孔隙率和大表面积。我们认为它可能作为一种从废水中去除重金属的试剂具有活性。本文在搅拌釜式反应器中研究了未萃取残渣去除六种金属离子（即Cu2+、Ni2+、Zn2+、Cd2+、Pb2+和Cr3+）的能力。获得的数据表明，在短时间内能够高效地从废水中去除金属离子，并且它们的浓度降低到法定限值以下，而不受物理和化学条件变化的明显影响。钠和钙离子取代水中的重金属，同时pH值几乎保持中性。确定了交换机制。
