Analytical chemistry in technical approaches: immobilization of biosorbent waste containing heavy metals in cemented materials

An ecologically safe and economically justified method of stabilization of the used biosorbents was developed. Sorbent contaminated with heavy metals has been successfully solidified/stabilized using a hydraulic binder. The test results indicated that up to 1% of the biosorbent residue used could be added without compromising the compressive strength of the mortar. The compressive strength of the modified mortars did not change significantly even after 20 freeze/thaw cycles. The analytical methods such as Flame Atomization-Atomic Absorption Spectrometer, Graphite Furnace-Atomic Absorption Spectrometer, and Cold Vapor-Atomic Absorption Spectrometry were utilized to examine the leaching behavior of selected heavy metals during harsh condition exposure. The leachability of selected heavy metals was found to be below the limit allowed by the US EPA after immersion and agitation for 10 days in artificial water solutions (seawater, groundwater, and rainwater). X-Ray Diffraction and Brunauer–Emmett–Teller data showed no significant changes in the crystalline structure and surface area of the modified mortars after treatment. Research showed that mixing the adsorbent used with mortar was effective in immobilizing heavy metals and allowed the implementation of a so-called ‘zero waste’ management method.

Graphical abstract