Study of Hg(ii) Removal From Aqueous Solution Using Lignocellulosic Coconut Fiber Biosorbents: Equilibrium and Kinetic Evaluation

Abstract

Lignocellulosic coconut wastes such as pith and fiber, which are abundantly available and cheap, have the potential of being used as low-cost biosorbents for heavy metal ion removal. In this study, pristine (CF-Pristine) and NaOH-treated (CF-NaOH) coconut fibers were used as a biosorbent for Hg(II) removal from an aqueous solution. The coconut fiber biosorbent (CFB) was characterized by scanning electron microscopy (SEM) and Fourier transform-infrared (FTIR) spectroscopy. The Hg(II) sorption capacities obtained for CF-Pristine and CFNaOH were 144.4 and 135.0 mg=g, respectively. Both the equilibrium and kinetic data of Hg(II) sorption onto CFB followed the Langmuir isotherm model and a pseudo-second-order kinetic model, respectively. A further analysis of the kinetic data suggested that the Hg(II) sorption process was governed by both intraparticle and external mass transfer processes, in which film diffusion was the rate-limiting step. These results demonstrated that both pristine-and alkali-treated coconut wastes could be potential low-cost biosorbent alternatives for the removal of Hg(II) from aqueous solutions, such as water containing Hg(II) produced in the oil and gas industry.

Removal performance of elemental mercury by low-cost adsorbents prepared through facile methods of carbonisation and activation of coconut husk

“…The Hg° is generally emitted to the environment from several anthropogenic sources, such as coal-fired power plants, municipal incinerators and wellhead natural gas processing (Padak et al, 2006;Reddy et al, 2014;Skodras et al, 2008). The research direction has been therefore towards the use of cheap adsorbent precusors, such as agriculture wastes (Hsi et al, 2011;Johari et al, 2014b;Saman et al, 2014;Song et al, 2013aSong et al, , 2013bTan et al, 2011Tan et al, , 2012. However, the search for even better and low-cost adsorbents has still been gaining considerable interests owing to the existing adsorbents being too costly to be used as pollution control strategies in many industrial processes.…”

Sustainable Conversion of Coconut Wastes into Useful Adsorbents

“…A similar study was conducted by Saman et al where coconut fiber was also utilized, but for adsorption of Ag(I) [107]. Unlike Johari et al [127], study by Saman et al shows that NaOH-treatment enhance Ag(I) removal as its adsorption capacity is higher compared to its pristine form [107]. According to Saman et al, the enhancement in Ag(I) adsorption is attributed to the increase in surface roughness and changes in chemical characteristics of the adsorbents.…”

“…Johari et al have conducted an extensive research and provided enough data on utilization of coconut fiber as adsorbent for heavy metal removal. In their study, Johari et al conducted a Hg(II) adsorption and compared the adsorbents' removal capabilities in their pristine and NaOH-treated form [127]. The studies found out NaOH treatment produced an adsorbent with rougher surface and pores that are larger and clearer compared to its pristine form.…”

Synergistic Study of Hydroxyiron (III) and Kaolinite Composite for the Adsorptive Removal of Phenol and Cadmium

“…Good adsorbents have specific properties such as large pores, availability of oxygen, hydrogen content and Hydroxyl group [21]. The FT-IR was carried using the KBr disk method [25].…”