Electrochemical heavy metal removal from water using PVC waste-derived N, S co-doped carbon materials

Abstract

N, S-codoped carbon materials derived from PVC plastic wastes were used for electrochemically removing heavy metal pollutants from water.

Porous Carbon–Carbon Composite Materials Obtained by Alkaline Dehydrochlorination of Polyvinyl Chloride

“…The removal of covalently bound chlorine during the liquid phase or mechanically activated dehydrochlorination of PVC under the action of alkalies (NaOH, KOH) has been studied quite well (see, for example, refs. [ 13 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]) and can be presented in the general form as a scheme in Figure 1 . The synthesis route is described in detail in the experimental section.…”

“…Catalytic dehydrochlorination is one of the promising directions [ 10 ]. At the same time, dehydrochlorination of PVC under the action of bases or alkalies remains the main reaction for this purpose [ 13 , 14 , 15 , 16 , 17 , 18 ]. Thus, hydrothermal treatment of a PVC powder in 1% aqueous solutions of NaOH [ 13 ] or Cu(NO 3 ) 2 [ 14 , 15 ] at a temperature up to 240 °C and a corresponding pressure leads to the removal of 94% and 98% chlorine from PVC, respectively; high degrees of chlorine removal from PVC (95–97%) were also achieved upon heating (170 °C and 200 °C) of the mixtures of PVC powders and Zn or Ca oxides [ 16 , 17 ], which, being the bases, served as dehydrochlorinating agents.…”

“…The indicated approach to the development of a dioxin-free process for utilizing chloropolymeric solid wastes will be economically attractive only if the carbon material (CM) obtained by dehydrochlorination of PVC finds its niche for commercial application; for example, if its structural parameters can hardly be achieved by the existing methods of CM synthesis. Thus, the authors of [ 18 ], when synthesizing carbon materials from PVC wastes, performed the dehydrochlorination step in a ball mill in the presence of KOH and thiourea, and the resulting product was thermally treated in a nitrogen flow at 600 °C. The produced carbon material had a high specific surface area (S BET = 1230 m 2 g −1 ) and a multilevel hierarchical macro/meso/microporous structure.…”

Surface and Structural Modulation of Waste‐Derived, Boron‐Doped Carbon to Enhance its Adsorption Efficiency for Lead Removal from Wastewater

“…In order to effectively remove heavy metal ions, Chang et al described the straightforward synthesis of N, S-co-doped carbon materials (NSÀ C) produced from PVC plastic wastes (HMIs). [23] Large specific surface area (1230 m 2 /g) and strong heteroatom doping (4.55 at % N and 13.30 at % S) were two characteristics of the NSÀ C. The CDI electrode made with NSÀ C demonstrated excellent regeneration capability for the adsorption of a variety of low-concentration heavy metal ions, including Fe 2 + , Co 2 + , Ni 2 + , Cu 2 + , Pb 2 + , and Cd 2 + , as well as high removal efficiency (94-99 %) and high capacity (36-62 mg/L). The Awal group created a conjugate adsorbent that uses a two-step procedure to simultaneously detect and remove harmful Pb(II) ions.…”

Critical Review of Bioadsorption on Modified Cellulose and Removal of Divalent Heavy Metals (Cd, Pb, and Cu)

“…However, reports on heavy metal contamination for the last two decades revealed tremendous increases in lead and cadmium concentrations in rivers and lakes across Africa, Asia, and Europe. , Inspite of different regulations and restrictions, preventing water pollution is still a challenge for humans. Thus, efforts to detect heavy metals and other pollutants − to alleviate water pollution have escalated over the years. − Various traditional and technological approaches that include sedimentation, ion exchange, chemical precipitation, coagulation, electrochemical methods, solvent extraction, adsorption, reverse osmosis, and ultrafiltration techniques have been extensively investigated and applied for heavy metal removal. − Figure depicts some water remediation methods. Unfortunately, the majority of the reported methods or techniques are associated with high cost, operational complications, low efficiency, excessive use of chemicals, and secondary pollutants that restrict their applications.…”