Evaluation of leaching behavior and immobilization of zinc in cement-based solidified products

Abstract

This study has examined leaching behavior of monolithic stabilized/solidified products contaminated with zinc by performing modified dynamic leaching test. The effectiveness of cement-based stabilization/solidification treatment was evaluated by determining the cumulative release of Zn and diffusion coefficients, De. The experimental results indicated that the cumulative release of Zn decreases as the addition of binder increases. The values of the Zn diffusion coefficients for all samples ranged from 1.210-8 to 1.1610-12 cm2 s-1. The samples with higher amounts of binder had lower De values. The test results showed that cement-based stabilization/solidification treatment was effective in immobilization of electroplating sludge and waste zeolite. A model developed by de Groot and van der Sloot was used to clarify the controlling mechanisms. The controlling leaching mechanism was found to be diffusion for samples with small amounts of waste material, and dissolution for higher waste contents

Effects of Mud from a Zinc-plating Plant and Zeolite Saturated with Zinc on Portland Cement Hydration and Properties of Hardened Cement Pastes

“…The measured values of thermovoltage are than processed on a computer program and calculated values of total heat released, the heat release rate and relative reaction degree for the first 48 hours of hydration. 28 The specific electrical conductivity is determined by Iskra MA 5964 microprocessor conductometer, Slovenia, connected to a computer via a RS 232 C digital output. The conductivity cell electrodes were made of stainless steel with a constant C = 0.285 cm -1 .…”

“…Its average chemical composition and physical properties are shown in Table 1. 27 As a supplementary material to cement was used natural zeolite (Donje Jesenje site, Krapina, Croatia) saturated with zinc ions. Saturation is carried out with a solution containing 9.0 mmol dm -3 ZnSO 4 .…”

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

“…The data obtained give a good perspective to develop an ecologically safe method for the management of used biosorbents without noticeable deterioration of the durability of the final cement-based product. Barbir et al [13] studied the leaching behavior of Zn in a modified cement-based material with sludge containing heavy metals and zeolite as a metal ion binder and found that enhancement of the binder content minimized the leachable concentration of metal ions in a liquid medium. This meant that the metal ions were successfully immobilized in cement-based materials.…”

“…The cement-based material acts as a hydraulic binder that traps contaminants within its matrix. Solidification/stabilization (S/S) is a simple process that allows toxic materials to be easily transported and stored, allowing the production of environmentally safe construction materials [13][14][15][16][17][18]. The approach based on the reuse of wastes in cement-based materials leads to avoiding unsterilized toxins that leach out of landfills (through the implementation of the ecocement approach) [19,20].…”

“…The mentioned additions could be expected to improve the compressive strength of the mortar by filling the pores of the mortar [23,24]. Potentially hazardous wastes such as radioactive waste [25], zinc (Zn(II)) [13], copper indium selenide (CIS), solar module wastes [26], arsenical borogypsum wastes [27], medical wastes [28], solid residues formed during sewage sludge thermal treatment [17], ceramic wastes [29], sugarcane bagasse [30], rice husk, disposed oil-contaminated soil [31], chromium-contaminated titania NPs [32], and coconut fibres [33] have all been trialled as incorporations into either cement matrices or concretes. The modified materials obtained have shown improved compressive strength and low leachability of metal ions.…”