Abstract
The present work demonstrated the removal of hexavalent chromium from aqueous solutions on synthesized graphene oxide (GO) from graphite. The prepared GO was characterized by various analytical techniques such as X-ray diffraction, scanning electron micrograph, Fourier transformed infrared and zero point change. The entire metal adsorption study was conducted through batch mode with keeping constant stirring rate (150 rpm). The operating variables such as pH (2–8), contact time (1–60 min), adsorbent dose (0.005 g–0.01 g L−1) and initial concentration (5–80 µg L−1) were considered, and optimized variables were fixed at maximum percentage of removal. The studied results ascertained that the maximum removal (92.8%) was achieved at acidic pH(4). The equilibrium of Cr(VI) adsorption data was nicely fitted with Langmuir model with maximum adsorption capacity (qm) 1.222 µg g−1. The sorption kinetics was nicely explained with pseudo-first-order and intraparticle diffusion mechanism. Thermodynamics of Cr(VI) adsorption revealed that the adsorption was spontaneous, endothermic and entropy-driven process. Therefore, it is concluded that graphene oxide could be an effective and efficient alternative toward removal of Cr(VI) from aqueous solution.
Highlights
Rapid growth of industrial development leads to excessive heavy metal load in the environment (Bhattacharya et al 2019)
After synthesis of graphene oxide (GO) from graphite, the optical absorption measurements were carried out by UV–visible spectrometric signature (Fig. 1) that clearly demonstrated the formation of GO which agrees with the literature value (Choi et al 2010)
It can be concluded that stable graphene oxide (GO) can be prepared from graphite under laboratory condition which again proved from spectroscopic study
Summary
Rapid growth of industrial development leads to excessive heavy metal load in the environment (Bhattacharya et al 2019). Many industries including tannery, electroplating, metal extraction, paints and pigments, chrome industries, etc., serve as the excellent source of heavy metals. Among the different toxic metals, chromium is considered as a potent toxic metal. It exists mainly in hexavalent [Cr(VI)] and trivalent [Cr(III)] states in the aquatic body. Hexavalent chromium is almost 1000 times greater toxic than trivalent chromium (Karthik and Meenakshi 2014).
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