Equilibrium Removal of Pb (II) Ions from Aqueous Solution onto Oxidized-KOH-Activated Carbons

Abstract

In the present study, the removal of Pb (II) ions on oxidized activated carbons (ACs) was investigated. ACs were derived from activation of indigenous cotton stalks waste with potassium hydroxide (KOH) in two-stage process. The KOH-ACs were subjected to liquid-phase oxidation with hot HNO 3 and one untreated sample was included for comparison. The obtained carbons were characterized by Fourier transform infrared (FTIR), slurry pH and N 2-adsorption at 77 K, respectively. Adsorption capacity of Pb (II) ions on the resultant carbons was determined by batch equilibrium experiments. The experimental results indicated that the oxidation with nitric acid was associated with a significant increase in mass of yield as well as a remarkable reduction in internal porosity as compared to the untreated carbon. The AC-800N revealed higher adsorption capacity than that of AC-800, although the former sample exhibited low surface area and micropore volume. It was observed that the adsorption capacity enhancement attributed to pore widening, the generation of oxygen functional groups and potassium containing compounds leading to cation-exchange on the carbon surface. These results show that the oxidized carbons represented prospective adsorbents for enhancing the removal of heavy metals from wastewater.

Removal of Cationic Neutral Red Dye from Aqueous Solutions using Natural and Modified Rice Straw

“…The nature and concentration of these groups might be modified by different oxidizing agent treatment methods [11][12][13][14].Thermal treatment is used for dry oxidation and concentrated nitric acid and concentrated urea are applied in wet oxidation. Oxidation may also influence the pore structure development.…”

Effect of Chemical Oxidation on the Adsorption Properties of Cationic Dye on Activated Carbons Prepared from Locally Atropa belladonna

“…After oxidation, this band is not observed and a broadening in the intensity of band located at 1630 cm -1 is occurred. Shoulder bands at 1458-1386 cm -1 conjugated with strong band at 1630 cm -1 may be ascribed to the presence of carboxylic acid, carbonyl-carbonates and quinones, also moieties such as C=N, C=C and NH 3 in aromatic rings [5][6][7][8][9][10][11]. Finally, the presence of C-H outof-plane bending vibrations in the aromatic ring is identified by the appearance of small bands at 800-420cm -1 .…”

“…Generally, the adsorption capacity of ACs significantly depended on their surface chemistry and is largely influenced by both quantity and type of the surface functional groups. Accordingly, many studies have considerable interests in the improvement of the surface chemistry properties of ACs via chemical oxidation and reported their relations with the adsorption of dyes and heavy metals in the last two decades [3][4][5][6][7][8][9][10][11][12][13].…”

“…Their final surface properties depend on the activation method, time of activation as well as oxidation process. Chemical activation of carbon feedstocks with H 3 PO 4 [3,6] KOH [5] and H 2 SO 4 [17,18] has attracted much attention because it causes strong polymerization through activation process. In this respect, it is substantial in the production of ACs to select low-cost raw materials that are rich in carbon content.…”

“…In addition, the remediation of wastewater sources contaminated by xenobiotic color organics is very required in issues of global environmental pollution to minimize their concentration and to recycle this water in further industrial or agricultural purposes. More than 1,00,000 kinds of dyes are available commercially, with over 7×10 5 tons of dyestuff that are produced annually. Dyestuff can be categorized based on their structure as anionic and cationic [20].…”