Chemical modifications of lignocellulosic materials and their application for removal of cations and anions from aqueous solutions

Abstract

This review discussed the last 10 years progress in the use of lignocellulosic materials chemically modified as low-cost biosorbents. Thus, the chemical modifications, such as chemical pretreatment, oxidation, as well as the grafting of carboxyl groups, amines, amides, etc., on lignocellulosic fibers, that aim to increase the number of adsorption sites and maximize toxic metal ion adsorption capacity have been addressed. The literature presents results that indicated performances of biosorbents equal to or even higher than conventional methods and adsorbents. Many efforts have been concentrated on the improvements of these biosorbents through chemical modifications. However, some difficulties still exist, including the discharge of colored organic compounds resulting from the pretreatments and the development of fast, clean, and low-cost synthesis of selective and multifunctional adsorbents. Thus, the challenge for future research is to find solutions to these difficulties in order to finally make lignocellulosics biosorbents that can replace conventional adsorbent materials.

Optimum Operating Conditions for the Removal of Phosphate from Water Using of Wood-Branch Nanoparticles from Eucalyptus camaldulensis

“…Conducting bio-sorption experiments were performed by shaking 0.1 g of nSD-KF with 10 mL (1:100 ratio) of phosphate solutions with various concentrations (5,10,20,40,80,160, and 320 mg/L). The agitation was conducted at 400 rpm for 2 h using orbital centrifuge to reach sorbate-sorbent equilibrium.…”

“…Bio-sorption is the use of biomaterials in the removal of pollutants from agricultural wastewater, where the P-loaded bio-sorbent can be reused as compost for land application in the form of supplemental phosphorus fertilizer. For the efficient and cost-saving removal of phosphate from water, the lignocellulosic biomaterials could be used in typical or modified forms [5][6][7]. Woody sawdust is one of these lignocellulosic biomaterial used for this purpose due to its chemical constituents including easily available functional groups such as OH, COOH, and NH 2 , and other compounds such as phenols, alcohols, and aldehydes that are presented in cellulose, lignin, and hemicelluloses.…”

Simultaneous removal of Cd, Co, Cu, Mn, Ni and Zn from synthetic solutions on a hemp‐based felt: Experimental design

“…The adsorbed amount decreased with an increasing concentration of electrolytes, especially in the case of cadmium which has the lowest value of Allred-Rochow 3,13,30,38 The presence of anions can lead to the formation of complexes that have a lower affinity for the adsorbent than free metal ions. In their comprehensive review on the use of lignocellulosic materials for the removal of cations from solutions, Melo et al 16 also reported that anions such as Cl 2 have an affinity for metal ions forming soluble and/or insoluble complexes. For example, chloride ions form stable complexes with Zn 21 thus suppressing Zn 21 and Zn(OH) 1 adsorption by the adsorbent.…”

“…Like all agricultural materials, after adsorption hemp-based felt can be incinerated to a much smaller volume of ash and/or recovery of adsorbed metal without adverse impact on the environment. Melo et al 16 reported that lignocellulosic materials form nontoxic sluge that can be easily processed and reused.…”

“…Many of them have been tested and proposed for pollutant removal. [15][16][17][18][19][20] The hemp plant (Cannabis sativa L.) deserves particular attention.…”