Composite nanofloral clusters of carbon nanotubes and activated alumina: An efficient sorbent for heavy metal removal

Enhanced removal of hexavalent chromium from aqueous media using a highly stable and magnetically separable rosin-biochar-coated TiO2@C nanocomposite

“…The dominant species of Cr(VI) at pH 2 to 6 are HCrO 4 1À and Cr 2 O 7 2À , while at pH higher than 6, the dominant species is CrO 4 2À . 11,56 The removal efficiency of Cr(VI) increased with the decrease in pH of the solution because the electrostatic attraction is strong between the adsorbent and adsorbate at low pH, while electrostatic repulsion is dominant at high pH. 34 At low pH, the surface charge of the adsorbent becomes positive due to the high concentration of H + in the aqueous solution, which increases the adsorption.…”

Recent Advances in Electrochemical Monitoring of Chromium

“…Most of the studies described above have shown that an adequate determination of hexavalent chromium requires an acidic medium. In general, for low concentrations of Cr(VI), the main reactions are (1) and (2) [ 53 , 54 ]: H 2 CrO 4 ⇆ HCrO 4 − + H + HCrO 4 − ⇆ CrO 4 2− + H + …”

Carbon nanotubes, graphene, and their derivatives for heavy metal removal

“…Benefiting from that, a maximum adsorption capacity of 258.6 mg/g and equilibrium adsorption rate of 20 min were obtained, which markedly outperformed the performance of reported 2D graphenebased adsorbents and many other conventional adsorbents. Sankararamakrishnan et al [142] used composite nanofloral clusters of CNTs and activated alumina for removal of Cd(II). CNTs were grown over Fe-and Nidoped activated alumina by chemical vapor deposition and washed with acid to produce nanofloral clusters.…”