2-Line ferrihydrite: synthesis, characterization and its adsorption behaviour for removal of Pb(ii), Cd(ii), Cu(ii) and Zn(ii) from aqueous solutions

Abstract

Nano-structured 2-line ferrihydrite was synthesized by a pH-controlled precipitation technique at 90 °C. Chemical, X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman analyses confirmed the sample to be 2-line ferrihydrite. The nano nature of the prepared sample was studied by transmission electron microscopy (TEM). The surface area obtained by the Brunauer-Emmett-Teller (BET) method was 175.8 m(2) g(-1). The nanopowder so obtained was used to study its behaviour for the removal of Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions. The relative importance of experimental parameters such as solution pH, contact time and concentration of adsorbate on the uptake of various cations was evaluated. By increasing the pH from 2.0 to 5.5, adsorption of the four cations increased. The kinetics parameters were compared by fitting the contact time data to both linear as well as non-linear forms of pseudo-second-order models. Linear forms of both Langmuir and Freundlich models fitted the equilibrium data of all the cations except for Pb(II) which was also fitted to the non-linear forms of both the models as it gave a low R(2) value of 0.85 for the Langmuir model. High Langmuir monolayer capacities of 366, 250, 62.5 and 500 mg g(-1) were obtained for Pb(II), Cd(II), Cu(II) and Zn(II), respectively. Presence of chloride or sulfate had an adverse effect on cation adsorption. The interactive effects on adsorption from solutions containing two, three or four cations were studied. Surprisingly no Cd(II) adsorption was observed in Pb(II)-Cd(II), Pb(II)-Cd(II)-Zn(II) and Pb(II)-Cd(II)-Cu(II)-Zn(II) systems under the studied concentration range. The overall loading capacity of the adsorbent decreased in mixed cation systems. Metal ion loaded adsorbents were characterized by XRD, FTIR and Raman techniques. The high adsorption capability of the 2-lines ferrihydrite makes it a potentially attractive adsorbent for the removal of cations from aqueous solutions.

Stability of iron minerals in Icelandic peat areas and transport of heavy metals and nutrients across oxidation and salinity gradients – a modelling approach

“…Our results indicating the high retention of phosphate, arsenate and lead by ferrihydrite are in good agreement with published data [26,27,28]. Poorly crystalline ferrihydrite, which has a high surface area, shows high retention capacity, but also so too do soils with high ferrihydrite content [29].…”

Facile preparation of mesoporous titanium nitride microspheres as novel adsorbent for trace Cd2+ removal from aqueous solution

“…Cd 2 þ concentration is decreased to 0.0015 mg L À 1 , which is far lower than the drinking water quality standards (0.005 mg L À 1 ) set by WHO [32]. However, most reports basically have been focused on the removal of high concentration Cd 2 þ from water and the final Cd 2 þ concentration is still higher than 0.06 mg L À 1 after treatment [33][34][35][36]. Furthermore, we also study the adsorption dynamics of the mesoporous TiN microspheres, as shown in Fig.…”

Adsorption of cadmium onto modified nanosized magnetite: kinetic modeling, isotherm studies, and process optimization

“…(2014) [1][2][3][4][5][6][7][8][9][10][11][12][13] www.deswater.com doi: 10.1080/19443994.2014.972986 phosphate fertilizers, and electroplating and manufacturing of batteries, pigments, and screens [5,7,8].…”

“…Heavy metal pollution of wastewater is always considered as the most common environmental threat due to the fact that venomous metal ions are potentially able to reach the top of the food chain and thus become a risk agent for human health [1][2][3][4]. In this regard, cadmium(II) is a toxic ion with significant environmental and occupational concerns [5,6].…”