Removal possibilities of colloidal chromium (III) oxide from water using polyacrylic acid

Małgorzata Wiśniewska,Katarzyna Szewczuk-Karpisz

doi:10.1007/s11356-012-1273-6

Małgorzata Wiśniewska, Katarzyna Szewczuk-Karpisz

Open Access

https://doi.org/10.1007/s11356-012-1273-6

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Abstract

The lack of water is the most serious threat to humanity that leads to more efficient water and sewage treatment. Currently, many scientists are looking for new coagulants, flocculants and physicochemical methods allowing for sufficient removal of pollutants from water. The presence of various types of pigments, including chromium (III) oxide, poses the major problem. Even small amounts of these substances inhibit life processes in water. In this paper, the stability of Cr2O3 suspension in the absence and the presence of polyacrylic acid (PAA) was determined. To explain the changes in the system stability, the adsorption and electrokinetic measurements were performed. The chromium (III) oxide suspension not containing PAA is the most stable at pH = 3. Under these conditions, each positively charged solid particle is surrounded by a negatively charged diffusion layer which protects from particle collision and aggregates formation (electrostatic stabilization). In turn, the Cr2O3 suspension containing the PAA is most unstable also at pH = 3. In this case, the polymer causes destabilization of the colloidal suspension, which results from charge neutralization of solid particles by adsorbed PAA.

Highlights

Nowadays, the lack of water is a significant problem in many countries
Stability measurements of chromium (III) oxide suspension in the absence and the presence of polyacrylic acid is needed to determine the optimal conditions for removal of chromium (III) oxide from water
The transmission and backscatter curves obtained at 25 °C for the following systems: Cr2O3, Cr2O3–polyacrylic acid (PAA) 2,000; Cr2O3–PAA 240,000 at pH03 and at two polymer concentrations (100 and 500 ppm) are shown in Figs. 1 and 2

Summary

Introduction

The lack of water is a significant problem in many countries. In 1995, 436 million people in 29 countries experienced water deficit. Poland has the poorest drinking water resources among all European countries because of its climatic and hydrologic conditions. Low rainfall and direct flow of groundwater to the Baltic Sea are responsible for the formation of water deficit areas in many Polish regions (Skośkiewicz 1996). The phenomenon of discharge of untreated or just mechanically treated sewages to rivers decreases the amount of available water, which could have been used in the food industry and transformed the Baltic Sea from oligotrophic to strong eutrophic type over the last century (Main Inspectorate of Environmental Protection 2011). Effective water and sewage treatments have become increasingly important in recent years

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