Chromium removal from aqueous solution by a PEI-silica nanocomposite

Abstract

It is essential and important to determine the adsorption mechanism as well as removal efficiency when using an adsorption technique to remove toxic heavy metals from wastewater. In this research, the removal efficiency and mechanism of chromium removal by a silica-based nanoparticle were investigated. A PEI-silica nanoparticle was synthesized by a one-pot technique and exhibited uniformly well-dispersed PEI polymers in silica particles. The adsorption capacity of chromium ions was determined by a batch adsorption test, with the PEI-silica nanoparticle having a value of 183.7 mg/g and monolayer sorption. Adsorption of chromium ions was affected by the solution pH and altered the nanoparticle surface chemically. First principles calculations of the adsorption energies for the relevant adsorption configurations and XPS peaks of Cr and N showed that Cr(VI), [HCrO4]− is reduced to two species, Cr(III), CrOH2+ and Cr3+, by an amine group and that Cr(III) and Cr(VI) ions are adsorbed on different functional groups, oxidized N and NH3+.

A systematic study of hexavalent chromium adsorption and removal from aqueous environments using chemically functionalized amorphous and mesoporous silica nanoparticles

“…Although the specific surface areas of NH 2 -ASNs and NH 2 -MSNs were lower than those of ASNs and MSNs, NH 2 -ASNs and NH 2 -MSNs had significantly higher Cr(VI) adsorption capacities (34.0 and 42.2 mg•g −1 , respectively) and removal efficiencies (61.9 and 76.8%, respectively). These values compare reasonably well with those reported for powder-like mesoporous silica, Stöber silica, and hybrid silica nanoparticles 27,39,76,100 . Furthermore, these results suggest both the introduction of nanoporous architecture and appropriate chemical functionalization of nanoparticle surfaces are essential for enhancing Cr(VI) adsorption and removal process.…”

“…In the present study, we used model systems and material characterization tools to investigate Cr adsorption on silica nanoparticles and the results suggest a structural and chemical rationale for enhanced Cr(VI) adsorption and removal. Second, the NH 2 -ASNs and NH 2 -MSNs examined converted most of the adsorbed Cr(VI) to relatively non-toxic Cr(III) at levels comparable to or marginally better than those reported for similar mesoporous silica systems 6,38,75,76,100 . Our results suggest Cr(VI) reduction is caused by a mixed adsorption-partial reduction process that may be characteristic of functionalized nanoparticle-based systems 6,73,101,102 .…”

Fabrication of PAN Electrospun Nanofibers Modified by Tannin for Effective Removal of Trace Cr(III) in Organic Complex from Wastewater

“…In the adsorption process, the influence of important parameters including TA content (0-5 wt %), solution pH value (1)(2)(3)(4)(5)(6)(7)(8), and contact time (10-240 min) on the adsorption of Cr(III) ions were researched by immersing 50 mg of nanofibers in Cr(III)-collagen solution in 250 mL flasks. The solution pH value was adjusted by using NaOH or HCl solution (0.1 mol L −1 ).…”

“…Chromium wastewater treatment is a focus of attention in industries such as dyeing and finishing, the electroplating industry, battery manufacturing and tanneries [1,2] because chromium ions in effluent can lead to severe environmental and health problems due to their non-biodegradability in living tissues [3][4][5]. Taking into consideration the toxicity of chromium, the maximum contaminant level (MCL) of total Cr in the discharge effluent is set at 1.5 mg L −1 in the leather industry of China.…”

Adsorption of Cu(II), Ni(II) and Zn(II) ions by nano kaolinite: Thermodynamics and kinetics studies

“…These heavy metals are considered high toxic metal, therefore the total limits of these metal ions concentration in water 0.05 mg/L and 1 mg/L in wastewater for use in irrigation (WHO, 2008;USEPA, 2004). Heavy toxic metal ions removal from water and industrial wastewater can be achieved by different treatment processes such as ion exchange (Kuhekar et al 2014), precipitation method (Minas et al, 2017), coagulation (Verma et al, 2013;Un et al, 2015), reverse osmosis (Tripathi and Dwivedi, 2012), electrochemical reductionprecipitation (Hu et al, 2017), ion flotation (Taseidifar et al, 2017), photocatalytic method (Wahyuni et al, 2015), membrane processes (Abu Qdais and Moussa, 2004;Canet et al, 2003), agricultural waste (Amer et al, 2015), Ceratonia siliqua bark (Farhan et al, 2012), rice husk (Asrari et al, 2010), modified loquat bark (Salem et al, 2014), Peanut shells and banana peels (Orhan and Buyukgungor, 1993), palm shell activated carbon (Onundi et al, 2010;Zhang et al, 2017;El-Sadaawy and Abdelwhaab, 2014;Bouhamed et al, 2015), graphene oxide , Ficus carcia leaves (Farhan et al, 2013), natural materials such as kaolinite clay (Kamel et al, 2004;Yavuz et al, 2003), natural clays (Bhattacharyya andGupta, 2006, Sdiri et al, 2014), natural bentonite (Mellah and Chegrouche, 1997), nano materials and composites (Oang et al, 2015;Choi et al, 2018;Shaofeng et al, 2005;Liu et al, 2014), alginate based nanocomposites (Esmat et al, 2017;Ebadi et al, 2016), natural materials such as sodium bentonite activated clay…”