Lignin-Based Magnesium Hydroxide Nanocomposite. Synthesis and Application for the Removal of Potentially Toxic Metals from Aqueous Solution

Abstract

The pollution of water by potentially toxic metals or socalled heavy metals is the most severe form of environmental impact. Nanocomposites are considered promising materials for the removal of potentially toxic metals from aqueous solution through adsorption or ion exchange. To produce high-performance adsorbent for the removal of Ni 2+ , Cd 2+ , and Pb 2+ , lignin−Mg(OH) 2 nanocomposite (LH-MH) was developed utilizing hydrolytic lignin waste with possible regeneration after metal uptake. The LH-MH was prepared using hydrolytic lignin, magnesium chloride, and NaOH solution by a thermally assisted method. The structure was studied using X-ray diffraction, transmission electron microscopy, and scanning electron microscopy, while chemical composition was evaluated by Fourier transform infrared spectroscopy, thermogravimetric analysis/differential thermogravimetry, and energy-dispersive X-ray spectroscopy mapping. Adsorption was described by the Langmuir and Sips models, whereas kinetics was elucidated by pseudo-first-order and pseudo-second-order models. The obtained material demonstrated a nanocomposite structure indicating well-distributed nano-Mg(OH) 2 onto the lignin polymer matrix. The nanocomposite demonstrated superior removal of Ni 2+ , Cd 2+ , and Pb 2+ . The mechanism of adsorption was investigated indicating ion exchange between toxic metals and Mg 2+ . The obtained adsorbent was successfully regenerated using combined treatment by HCl−MgCl 2 −NaOH.

Plant celluloses, hemicelluloses, lignins, and volatile oils for the synthesis of nanoparticles and nanostructured materials

“…379 The other examples of recently fabricated lignin-based nanosized composites include, e.g., lignin-silica nanocomposites by grafting quaternary ammonium groups in softwood Kraft lignin with a core-shell structure and controlled mesopores as a sorbent, 380 lignin nanosphere-polymer of vinyl alcohol nanocomposite with UV absorbing properties, 381 nanosized lignin-polycaprolactone composites as tissue scaffolds, 382 graphenelignin nanocomposite derivative of carbon film for energy storage application 383 and ligninbased magnesium hydroxide nanocomposite for toxic metal removal from aqueous medium. 384 Table 8 summarizes the different applications of nanolignin materials.…”

Lignin Nanoparticles: A Promising Tool to Improve Maize Physiological, Biochemical, and Chemical Traits

“…Another promising application that involves lignin, as nanoparticles or not, is its use as a valuable macromolecule for environmental remediation [ 9 ]. To this end, lignin has been successfully employed for removing toxic substances from the environment (soil and water), and in particular heavy metals [ 9 , 10 , 11 ].…”

“…Another promising application that involves lignin, as nanoparticles or not, is its use as a valuable macromolecule for environmental remediation [ 9 ]. To this end, lignin has been successfully employed for removing toxic substances from the environment (soil and water), and in particular heavy metals [ 9 , 10 , 11 ]. In addition, agriculture is trying to implement this type of nanoparticles for the controlled release of agrochemicals and fertilizers [ 4 , 12 , 13 , 14 ].…”

Carbohydrate biopolymers, lignin based adsorbents for removal of heavy metals (Cd2+, Pb2+, Zn2+) from wastewater, regeneration and reuse for spent adsorbents including latent fingerprint detection: A review

“…It was recovered with HCl, NaOH and MgCl 2 after the adsorption of heavy metals. LH-MH therefore worked effectively for the adsorption of toxic heavy metals from aqueous solution [ 70 ].…”