Nanoporous carbon materials as a sustainable alternative for the remediation of toxic impurities and environmental contaminants: A review

Due to rapidly deteriorating water resources, the world is looking forward to a sustainable alternative for the remediation of noxious pollutants such as heavy metals and organic and gaseous contaminants. To address this global issue of environmental pollution, nanoporous carbon materials (NPCMs) can be used as a one-stop solution. They are widely applied as adsorbents for many toxic impurities and environmental contaminants. The present review provides a detailed overview of the role of different synthesis factors on the porous characteristics of carbon materials, activating agents, reagent-precursor ratio and their potential application in the remediation. Findings revealed that synthetic parameters result in the formation of microporous NPCMs (S-BET: > 4000 m(3)/g; V-Total (cm(3)/g) >= 2; V-Micro (cm(3)/g) >= 1), micromesoporous (S-BET: > 2500 m(3)/g; V-Total (cm(3)/g) >= 1.5; V-Micro (cm(3)/g) >= 0.7) and mesoporous (S-BET: > 2500 m(3)/g; V-Total (cm(3)/g) >= 1.5; V-Micro (cm(3)/g) >= 0.5) NPCMs. Moreover, it was observed that a narrow pore size distribution (0.5-2.0 nm) yields excellent results in the remediation of noxious contaminants. Further, chemical activating agents such as NaOH, KOH, ZnCl2, and H3PO4 were compared. It was observed that activating agents KOH, H3PO4, and ZnCl2 were generally used and played a significant role in the possible large-scale production and commercialization of NPCMs. Thus, it can be interpreted that with a well-planned strategy for the synthesis, NPCMs with a tuned porosity for a specific application, in particular, microporosity for the accumulation and adsorption of energetically important gases (CO2, CH4, H-2), micro-mesoporosity and mesoporosity for high adsorption capacity for towards metal ions and a large number of dyes, respectively.

Automated summary

This paper presents the application of nanoporous carbon materials in environmental pollution remediation and summarizes the effects of synthesis factors on the characteristics of porous carbon materials and the role of activating agents.