Modified sorbents based on soda production sludge for extracting ions of heavy metals from aqueous solutions waste water
I. S. Glushankova, E. V. Kalinina, E. N. Demina
Section: Ecologization of industry
The purification of industrial and surface wastewater from heavy metal ions (HMI) to requirements for the discharge
of treated wastewater into natural waters is one of the most complicated environmental and technological problems. For
the deep purification of waste water from the HMI, the use of cheap sorbents obtained from production waste is the most
promising. One of the many-tonnage wastes of technology of inorganic substances is the sludge formed in the production
of soda by the ammonia Solvay,s method. Currently, sludge is stored in sludge accumulators and is a long-term source
of pollution of environmental objects. Scientific developments in the utilization of slimes with the production of building materials, etc., have not found wide practical use, which is due to the heterogeneity of the granulometric and chemical
composition of the waste. Carried out X-ray phase analysis and studies of the physicochemical and chemical properties
of waste samples showed that its main components are calcium carbonate (calcite) and calcium hydroxide (portlandite).
It is known that the natural mineral limestone efficiently extracts HMI from aqueous solutions with the formation of
less soluble basic salts, carbonates, and hydroxy carbonates of HM. It has been established that sludge samples have
high sorption activity when copper(II) and zinc ions are extracted from low concentrated solutions (sorption capacity for
copper ions is 35.0 mg/g, sorption capacity for zinc ions is 40 mg/g). To increase the operational properties, a method
has been developed for the production of a modified granular sorbent based on the sludge of soda production, consisting
in treating with sodium silicate. The effect of a dose of sodium silicate in the sorbent composition on the mechanical
strength and sorption properties of the obtained samples was studied. It has been established that the introduction of 8,6%
SiO2 into the sludge leads to an increase in the mechanical strength by 50–80%, and does not have a significant effect
on the sorption activity of the material. The kinetic and sorption regularities of extraction of copper(II) ions and zinc on
modified sorbents are revealed. Based on the analysis of the adsorption isotherms obtained, the adsorption equilibrium
constants and maximum adsorption values (Amax (Cu2+) = 50.8 mg/g; Amax (Zn2+) = 97.1 mg/g) were determined.
Obtained sorption materials can be recommended for wastewater treatment from HMI.
Keywords: heavy metals ions, soda production sludge, calcium carbonate, sorbents, sorption capacity
Article published in number 3 for 2018 DOI: 10.25750/1995-4301-2018-3-100-108
ISSN 1995-4301
Select viewing options
