Feasibility of mercury (II) ion removal by nitrated polycarbonate derived from waste optical discs

Abstract

Advanced technology has led to the generation of the massive amount of electrical and electronic wastes, including compact discs and digital versatile discs. These optical discs are often ended up in landfills and incinerators, resulting in severe environmental degradation. This research aims to recover polycarbonate from waste optical discs and exploring its potential as a sorbent for the removal of mercury in water. The recovered polycarbonate was nitrated to enhance its efficiency in removing mercury (II) ion. The nitrated polycarbonate was characterized using Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, energy-dispersive X-ray spectroscopy and Brunauer-Emmett-Teller surface area analysis. Response surface methodology was employed to investigate the effects of agitation rate, contact time, pH, initial concentration, sorbent dosage on the mercury (II) ion removal efficiency via a central composite design. According to the quadratic model, an optimum response can be achieved at 188.6 rpm of agitation, 150 min of contact time, pH 7.55 and 1.50 mg/L of initial mercury (II) ion concentration. The adsorption process was found to follow the Freundlich isotherm model, and the adsorption mechanism was found to obey the pseudo-second-order kinetic model that indicates the chemisorption process. The results of this study showed that the nitrated PC with a maximum adsorption capacity of 0.289 mg/g has the potential to be used as a sorbent in water treatment for the removal of mercury (II) ion in water.

Poly(4-vinylphenol) coated magnetic nanoparticles based dispersive solid-phase microextraction of the determination of mercury(II) in water

“…When the pH was increased to pH 4, the phenol group of PVP was ionized to form negatively charged phenolate, which could interact favorably with Hg 2+ via ionic interaction. As reported by Abdallah et al (2020), water-soluble Hg(OH)2 is the main species at pH 5 and above. The high removal efficiency of Hg 2+ at high pH indicated that Hg(OH)2 interacted favorably with PVP@MNP.…”

“…However, the percentage removal was increased significantly to 99.9% when the pH was varied from 4.0 to 9.0 (Figure 3c). At pH 3, the low removal efficiency of Hg 2+ was because of the competition between H + with Hg 2+ and Hg(OH) + for the active sites of PVP@MNP (Abdallah et al, 2020). When the pH was increased to pH 4, the phenol group of PVP was ionized to form negatively charged phenolate, which could interact favorably with Hg 2+ via ionic interaction.…”

“Functional upcycling” of polymer waste towards the design of new materials

“…20e and Table 9(5)). 583,[585][586][587] However, such methods are discouraged by a relatively low functionalisation degree 570,588 and the use of aggressive chemicals that generate toxic greenhouse NO 2 . Nitrogen-containing groups can be further reduced by sodium borohydride to amino.…”

“…21a and Table 9(5)). 579,583 Despite the relatively moderate adsorption capacity of PCs (0.289 mg g À1 ) compared to carbon materials, 604 PC can be used as a sustainable sorbent for wastewater treatment. The developed chemistry of PC (Fig.…”

“…Fig. 20 Functionalisation of PC: (a) nitrene functionalisation; 571-573 (b) surface hydrolysis; 574-577 (c) surface amination; 548,578-581 (d) surface phosphorylation;582 (e) nitration[583][584][585][586][587][588] /sulfonation 586 /chloromethylation; 588 (f) Friedel-Crafts alkylation for hyper-cross-linking; 377 and (g) UV-irradiation or plasma or ozone 586,[589][590][591][592][593][594]. …”