Hexavalent chromium removal by using synthesis of polyaniline and polyvinyl alcohol

Abstract

Over the past few years, heavy metals have been proved to be one of the most important contaminants in industrial wastewater. Chromium is one of these heavy metals, which is being utilized in several industries such as textile, finishing and leather industries. Since hexavalent chromium is highly toxic to human health, removal of it from the wastewater is essential for human safety. One of the techniques for removing chromium (VI) is the use of different adsorbents such as polyaniline. In this study, composites of polyaniline (PANi) were synthesized with various amounts of polyvinyl alcohol (PVA). The results showed that PANi/PVA removed around 76% of chromium at a pH of 6.5; the PVA has altered the morphology of the composites and increased the removal efficiency. Additionally, synthesis of 20 mg/L of PVA by PANi composite showed the best removal efficiency, and the optimal stirring time was calculated as 30 minutes. Moreover, the chromium removal efficiency was increased by decreasing the pH, initial chromium concentration and increasing stirring time.

Immobilization of Cr(VI) in Soil Using a Montmorillonite-Supported Carboxymethyl Cellulose-Stabilized Iron Sulfide Composite: Effectiveness and Biotoxicity Assessment

“…Cr(III) and Cr(VI) are two common species of Cr in the environment. Cr(III)-which comes from insoluble substances such as Cr(OH) 3 and Cr 2 O 3 -has a relatively low biotoxicity and is more stable; Cr(VI)-which comes from compounds such as CrO 4 2− , HCrO 4 − , and Cr 2 O 7 2− -is easier to mobilize than Cr(III), particularly in soil [6][7][8].…”

Sorption enhancement of Cr(VI) from aqueous solution by polyaniline confined in three-dimensional network of composite porous hydrogel

“…In recent years, PVA-based hydrogels have attracted considerable attention in the eld of adsorption because of their non-toxicity, low cost, simple preparation, directional adjustment function and fast adsorption rate(Chen et al, 2020;Gulyuz &Arslan, 2021;Sun et al, 2015). PVA-based hydrogel as carrier can provide a uniform system for aniline polymerization, effectively improve the problem of easy agglomeration of aniline polymerization, and improve its mechanical strength and processability.Composite hydrogel is an excellent adsorbent for removing Cr (VI), which has the dual advantages of hydrogel and conductive polymer(RiahiSamani et al, 2016). Emulsion polymerization is one of the ideal strategies to obtain porous hydrogels, but the traditional surfactant-stabilized emulsion often has the disadvantages of foaming, high toxicity and high cost(Yuan et al, 2020).…”