Use of red mud from amazon region as an adsorbent for the removal of methylene blue: process optimization, isotherm and
- PDF / 2,044,185 Bytes
- 16 Pages / 595.276 x 790.866 pts Page_size
- 62 Downloads / 216 Views
ORIGINAL PAPER
Use of red mud from amazon region as an adsorbent for the removal of methylene blue: process optimization, isotherm and kinetic studies Y. J. C. Martins1 · A. C. M. Almeida2 · B M. Viegas3 · R. A. do Nascimento3 · N. F. da P. Ribeiro1 Received: 27 September 2019 / Revised: 2 April 2020 / Accepted: 24 April 2020 © Islamic Azad University (IAU) 2020
Abstract The aim of this study is to evaluate the potential of red mud applied as an adsorbent in the removal of dyes from the textile industry; the adsorption process was optimized using both response surface methodology and desirability function. Scanning electron microscopy (SEM), X-ray diffraction (XRD), point of zero charge (pHPZC), nitrogen physisorption and thermogravimetric analysis techniques were used to characterize the adsorbent. Adsorption process was based on an experimental design, where contact time (5 and 60 min), pH of the medium (4 and 6.5) and adsorbent concentration (5 and 10 mg L−1) were the independent variables. In addition, the kinetic mechanism and adsorption equilibrium were investigated. The results indicated that a higher removal efficiency of methylene blue was obtained at higher adsorbent concentrations (8–10 mg L −1) and lower pH ranges (4.0–5.0), while increasing the adsorptive capacity is achieved by decreasing the adsorbent concentration and pH. The optimum adsorption conditions were: 60 min, a pH of the medium at 4.0 and adsorbent concentrations of 8.66 and 10 g L−1. The equilibrium data were fit to the Langmuir equation (R2 = 0.993) with a maximum adsorption capacity of 6.541 mg g−1. Experimental measurements showed that the adsorption kinetics corresponded to a pseudo-second-order reaction (R2 = 0.998) with the chemisorption as the process controlling step. The results obtained in this work indicated that red mud can be an alternative for the removal of pigments in wastewater treatment processes in an efficient and economical way. Graphic abstract
Keywords Adsorption · Analysis of variance · Chemisorption · Dyes · Langmuir
Editorial responsibility: M. Abbaspour. * R. A. do Nascimento [email protected] Extended author information available on the last page of the article
13
Vol.:(0123456789)
International Journal of Environmental Science and Technology
Introduction Bauxite residue, or red mud (RM), is a solid by-product generated during bauxite processing for the production of alumina. This residue comes from the Bayer process, which uses sodium hydroxide to dissolve the alumina present in bauxite. It is estimated that approximately 150 million tons of red mud are generated annually around the world (Evans 2016). The RM/bauxite production ratio is approximately 1.5/1.0 tonnes. However, this proportion may vary according to the mineralogical properties of bauxite and the location of the deposit (Muzika et al. 2019). In 2015, China, Oceania and South America accounted for 50.4%, 18.6% and 11.6% of the global production of alumina, respectively (Hua et al. 2017). The red mud consists of insoluble meta
Data Loading...
