Efficient removal of dyes from aqueous solutions using a novel hemoglobin/iron oxide composite

Authors: ESSANDOH, MATTHEW - Orise Fellow; Garcia, Rafael

Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2018
Publication Date: 5/10/2018
Citation: Essandoh, M., Garcia, R.A. 2018. Efficient removal of dyes from aqueous solutions using a novel hemoglobin/iron oxide composite. Chemosphere. 206:502-512. https://doi.org/10.1016/j.chemosphere.2018.04.182.
DOI: https://doi.org/10.1016/j.chemosphere.2018.04.182

Interpretive Summary: Dyes are used in a variety of industries including paper, paint, textile, and leather manufacture. Unfortunately, dye-contaminated wastewater is well known as one of the most polluting industrial wastewaters. These industries that utilized dyes release huge amount of unused dyes into the environment. Even low concentration of dyes in effluent from these industries significantly decrease the quality of water and are highly undesirable as they cause harmful effect in the environment and also to humans. Water that is contaminated with dyes is typically treated with substances called adsorbents. These adsorbents are materials that can extract chemicals from solid, liquid or gases onto their surface. Currently, many of adsorbent sold on the markets to remove chemicals are very expensive, hard to recover and recycle, and above all suffers from high activation and reactivation cost. However, hemoglobin (Hb) is a component of blood, and it can be obtained inexpensively from waste slaughterhouse blood. Hb has both positive and negative charges on its surface and therefore may serve as a good candidate for its attachment or attraction to other chemicals. In this study, Hb was modified with iron oxide, to form a new composite that has the ability to extract different kinds of dyes from aqueous solutions. The results show that the new composite produced had the desired effect of removing six different dyes from aqueous solutions. The composite can be tested as adsorbent for other chemicals like heavy metals and pesticides. This research has provided a simple, inexpensive way to prepare and utilize hemoglobin-based adsorbent for the first time. This research will also help convert waste generated from slaughterhouses into a useful product such as adsorbent.

Technical Abstract: Magnetic particles entrapped in different matrices that display high thermal stability, low toxicity, interactive functions at the surface, and high saturation magnetization are of great interest. The objective of this work was to synthesize a novel hemoglobin/iron oxide composite (Hb/Fe3O4) for the removal of six different dyes (indigo carmine, naphthol blue black, tartrazine, erythrosine, eriochrome black T and bromophenol blue) from aqueous solutions. Hb/Fe3O4 composite was prepared by using alkaline solution to induce iron oxide particle formation on hemoglobin from an aqueous Fe3+ and Fe2+ salts. The Hb/Fe3O4 composite was characterized using scanning electron microscopy (SEM), laser diffraction particle size analysis, FT-IR spectroscopy, isoelectric point determination and thermogravimetric analysis (TGA). The techniques employed revealed alteration of Hb after magnetization. The Hb/Fe3O4 composite showed high removal efficiency toward all the different classes of dyes studied. Adsorption was found to follow pseudo-second order kinetic model and Langmuir isotherm. The Langmuir monolayer adsorption capacities for all the six dyes range from 80 to 178 mg/g. The Hb/Fe3O4 composite possesses extra advantage of being easily isolated from aqueous suspension using an external magnet. The reusability of the prepared Hb/Fe3O4 composite was also demonstrated by recycling at least four times with 98% of the initial adsorption capacity remaining. The prepared Hb/Fe3O4 composite are useful for subsequent functionalization reactions and have potential for various applications.