Rożek Piotr, Florek Paulina, Król Magdalena, Mozgawa Włodzimierz
Faculty of Materials Science and Ceramics, AGH University of Science and Technology, 30 Mickiewicza Av., 30-059 Krakow, Poland.
Materials (Basel). 2021 Jan 4;14(1):214. doi: 10.3390/ma14010214.
Boroaluminosilicate geopolymers were used for the immobilization of heavy metals. Then, their mechanical properties, phase composition, structure, and microstructure were investigated. The addition of borax and boric acid did not induce the formation of any crystalline phases. Boron was incorporated into the geopolymeric network and caused the formation of N-B-A-S-H (hydrated sodium boroaluminosilicate) gel. In the range of a B/Al molar ratio of 0.015-0.075, the compressive strength slightly increased (from 16.1 to 18.7 MPa), while at a ratio of 0.150, the compressive strength decreased (to 12 MPa). Heavy metals (lead and nickel) were added as nitrate salts. The loss of the strength of the geopolymers induced by heavy metals was limited by the presence of boron. However, it caused an increase in heavy metal leaching. Despite this, heavy metals were almost entirely immobilized (with immobilization rates of >99.8% in the case of lead and >99.99% in the case of nickel). The lower immobilization rate of lead was due to the formation of macroscopic crystalline inclusions of PbO·xHO, which was vulnerable to leaching.
硼铝硅酸盐地质聚合物被用于固定重金属。然后，对其力学性能、相组成、结构和微观结构进行了研究。硼砂和硼酸的添加并未诱导任何晶相的形成。硼融入地质聚合物网络并导致形成N-B-A-S-H（水合硼铝硅酸钠）凝胶。在B/Al摩尔比为0.015 - 0.075的范围内，抗压强度略有增加（从16.1 MPa增至18.7 MPa），而在比例为0.150时，抗压强度降低（至12 MPa）。重金属（铅和镍）以硝酸盐形式添加。硼的存在限制了重金属引起的地质聚合物强度损失。然而，这导致了重金属浸出增加。尽管如此，重金属几乎完全被固定（铅的固定率>99.8%，镍的固定率>99.99%）。铅的固定率较低是由于形成了易浸出的PbO·xHO宏观晶体夹杂物。
