Application of hybrid bead, persimmon leaf and chitosan for the treatment of aqueous solution contaminated with toxic heavy metal ions

Abstract

In this study, hybrid beads, which are made by mixing persimmon leaf and chitosan, was used to remove Pb(II) and Cd(II) from aqueous solution. According to the Fourier transform infrared spectrometry (FT-IR) analysis, the hybrid bead has a structure that enables the easy adsorption of heavy metals because it has carboxylic, carbonyl groups, O-H carboxylic acid, and bonded -OH groups. The adsorption of Pb(II) and Cd(II) by hybrid beads was more suitable with the Langmuir isothermal adsorption and showed an ion exchange reaction which occurred in the uneven adsorption surface layer. The maximum adsorption capacity of Pb(II) and Cd(II) was determined to be 278.68 mg/g and 87.91 mg/g, respectively. Furthermore, the adsorption removal process of Pb(II) and Cd(II) using hybrid beads is a spontaneous exothermic reaction and the affinity of the adsorbed material for the adsorbent is excellent. Hybrid beads are inexpensive, have a high removal efficiency of heavy metals, and are environmentally friendly.

Assessment of the adsorption kinetics, equilibrium, and thermodynamic for Pb(II) removal using a low‐cost hybrid biowaste adsorbent, eggshell/coffee ground/sericite

“…The adsorption process includes four steps: bulk transport, film diffusion, intraparticle diffusion, and adsorption of the material on the adsorbent (Yu & Choi, ). The adsorption rate is determined by two stages of film diffusion and three stages of intraparticle diffusion (Georgescu et al, ).…”

“…Adsorption occurs by ionic or intermolecular interactions between the adsorbate and adsorbent surface (Yu & Choi, ). Therefore, the adsorption process is influenced by the temperature and pH of the aqueous solution; concentration and molecular size of the adsorbate; and structure, polarity, specific surface area, and pore size of the adsorbent (Choi et al, ; Edathil, Shittu, Zain, Banat, & Haija, ).…”

“…Lead is a multifunctional metal that is used in the manufacture of pipes, paints, and bullets and is commonly used in the alloy industry (Choi, ). Lead is less toxic than cadmium and mercury, but its emissions are the highest among heavy metals (Yu & Choi, ). The World Health Organization (WHO), therefore, regulates the release of lead to levels below 0.01 ppm, which is also the case for arsenic or selenium (WHO, ).…”

“…The World Health Organization (WHO), therefore, regulates the release of lead to levels below 0.01 ppm, which is also the case for arsenic or selenium (WHO, ). Thus, various studies have been conducted on the removal of lead from aqueous solutions (Ahmad et al, ; Barsbay, Kavaklı, Tilki, Kavaklı, & Güven, ; Choi, ; Choi et al, ; Singh, Nagpal, Agrawal, & Rachna, ; Yu & Choi, ).…”

“…In contrast, heavy metal removal processes using biological adsorption techniques have the advantages of low operating costs and heavy metal recovery, the ability to reuse the biodegradable absorbents, and can minimize the volume of sludge to be treated (Choi & Yu, ). However, bio‐adsorption has the disadvantages of a low adsorption efficiency and long processing time (Yu & Choi, ). Recently, many researchers have studied methods to remove heavy metals from aqueous solutions using biomaterials and wastes (Chen, Shah, Shi, & Chiang, ; Khatoon, Uddin, & Rao, ; Lee & Choi, ; Singh et al, ).…”