Activated carbons for the removal of heavy metal ions: A systematic review of recent literature focused on lead and arsenic ions

Abstract

This work is a systematic review of the literature over the past decade of the application of activated carbon (microporous or mesoporous) as adsorbents for the removal of heavy metals, focusing especially on lead (Pb) and arsenic (As) ions from the aqueous phase. Classical examples from our lab are also given. Activated carbon is known to provide a high surface area for adsorption. Generally, surface modification is typically required, such as oxidation, treatment with ammonia or even impregnation with ferric ion, etc. and the adsorbent material may originate from various sources. The pristine materials, after modification and those after batch-wise adsorption, were characterized by available techniques (BET analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, thermal analyses, X-ray photoelectron spectroscopy). Adsorption isotherms, thermodynamics and kinetics of the process are also discussed. Selected studies from the literature are examined in comparison with other adsorbents. The role of chemistry in the metals adsorption/removal was investigated.

Synthesis of magnetically separable and recyclable magnetic nanoparticles decorated with β-cyclodextrin functionalized graphene oxide an excellent adsorption of As(V)/(III)

“…Irrespective of the charge on the surface of β-CDs-GO@Fe 3 O 4 NPs, it's expected to increase of As(V) adsorption in acidic pH [20,21]. It has been well documented in earlier studies, the anionic arsenic species [H 2 AsO 4 − &HAsO 4 2− ] get adsorbed with the positively charged adsorbent (GO-OH 2 + , GO-COOH 2 + , Fe-OH 2 + ) by electrostatic attraction (Fig. 8E).…”

“…is depending on the pH values, and also phosphates can exist in any of the following four forms in dilute aqueous solution: phosphate ion (are more prevalent in strong basic conditions, HPO4 2− ions are more likely to appear in weak basic conditions. Furthermore, H 2 PO 4 − ions and aqueous H 3 PO 4 predominate in weak and strong acid conditions, respectively.To summarize, the effect of competing anions to the adsorption of As(− , the stronger interactions of these competing…”

Flotation in Water and Wastewater Treatment

“…Activated carbons are among the effective adsorbents because of their excellent sorption capacity, and their microporous nature is generally well suited to many applications; although their use has been often prohibited mainly due to their relatively high cost, low selectivity, and regeneration problems [35]. Thiourea (CS(NH 2 ) 2 ), on the other hand, presents an alternative lixiviant to cyanide, applied in acidic media for gold recovery.…”

Zero-Cost Agricultural Wastes as Sources for Activated Carbons Synthesis: Lead Ions Removal from Wastewaters

“…In the present study, based on our previous experience/knowledge in activated carbons and low-cost adsorbent materials [4,5,[13][14][15][16][17][18][19][20][21], activated carbons were produced from agricultural wastes by hydrothermal treatment of potato peels. All samples were activated using KOH at 400 °C.…”