Adsorptive Removal of Lead and Chromate Ions from Water by Using Iron-Doped Granular Activated Carbon Obtained from Coconut Shells

Abstract

In this study, a low-cost granular activated carbon doped with Fe2O3 nanoparticles (Fe–GAC) was prepared via a modified sol-gel technique and utilized for the elimination of lead (Pb(II)) and chromium (Cr(T)) ions from synthetic and actual brackish water. The effect of adsorption parameters on the removal of Pb(II) and Cr(T) ions from the water was evaluated in batch adsorption tests. The characterization results validated the distribution of well-defined Fe2O3 nanoparticles onto the GAC surface. GAC loaded with 5 wt.% of Fe2O3 (Fe–GAC 5) exhibited a maximum surface area of 848.2 m2 g−1. The equilibrium data of Cr(T) adsorption were in close agreement with the Langmuir and Sips models with R2 values of 0.95 and 0.96, respectively. However, the R2 values of the equilibrium data for Pb(II) adsorption were greater than 0.91 for all four models, i.e., Langmuir, and Sips, Freundlich and Redlich-Peterson. The maximum Langmuir adsorption capacities of Pb(II) and Cr(T) by Fe–GAC 5 at pH 5.6 and room temperature were 11.9 and 22.1 mg g−1, respectively. Pseudo-second order (R2Pb(II) = 0.99, R2Cr(T) = 0.99) and Elovich kinetic models (R2Pb(II) = 1, R2Cr(T) = 1) were found the most suitable for describing the adsorption kinetics data of Pb(II) and Cr(T) using Fe–GAC 5. The adsorption/desorption studies illustrated that the Fe–GAC is reusable and can be regenerated using 1.0 M HCl. Moreover, the Fe–GAC 5 was found effective to reduce heavy metals loading in actual brackish water to the allowed international standards of drinking water. Accordingly, the Fe–GAC could be a promising material for large-scale applications for the elimination of heavy metals from water.

Removal of rhodamine b and alizarin red from aqueous solutions by oxidized carbon nanotubes: kinetics and isotherm Study

“…The peaks detected at 1300-1500 cm -1 corresponded to C-C stretching vibrations, indicating the existence of sp2 hybridized carboncarbon bonds. Finally, the peaks observed at 500-800 cm -1 corresponded to C-H bending vibrations [13].…”

Co-Al layered double oxide activated carbon composite for eliminating lead ions from water

“…As depicted in Figure 4(c), it was clearly shown that by improving the pHi from 2.2 to 5.9, the Pb 2+ elimination efficiency has dramatically increased from 9.1% to 99.2% with an upsurge in the adsorption uptake from 2.15 mg/g to 23.52 mg/g. After pH 6, some studies reported an improvement in the elimination efficiency of Pb 2+ ions which was ascribed to the formation of Pb 2+ hydroxide precipitation [23], [40]. At pH 2.2, the adsorbent holds a highly positive charge explaining the low adsorption capacity at this pH.…”

Preparation and characterization of clay based ceramic porous membranes and their use for the removal of lead ions from synthetic wastewater with an insight into the removal mechanism

“…Therefore, it is essential to explore new methods of separating and recovering this metal in its dissolved form from the environment. Many methodologies have been used for Pb 2+ removal; the adsorption, coagulation, and flocculation are among the widely used techniques [ 2 , 3 ]. Furthermore, ceramic membranes have proven to be strong mechanically, thermally, and stable compared to other membrane categories.…”