Recent advances of greener pretreatment technologies of lignocellulose

Assessment of sulfonation in lignocellulosic derived material for adsorption of methylene blue

“…However, many researchers emphasized that the adsorption of MB affects the surface acidity of carbon by various surface functional groups such as phenol and carboxyl groups due to the influence of electrostatic interactions with the adsorbent. It was confirmed by several researchers that such surface acidity affects the adsorption efficiency of MB [6,12,[20][21][22].…”

“…In the adsorption process, when the mixture of the solution and the adsorbent is not uniform, the concentration of the adsorbent is low, the particle size of the adsorbent is small, and the adsorbent has a high affinity with the adsorbent, the transfer of external substances determines the adsorption rate [3,32]. On the other hand, when the mixture of the solution and the adsorbent is smooth, the particle size of the adsorbent is large, the concentration of the adsorbent is high, and the affinity between the adsorbent and the adsorbent is low, intraparticle diffusion is the rate determining step [12,25]. In the internal particle diffusion model, the value of the constant C representing the thickness of the boundary layer indicates whether adsorption is controlled only by internal diffusion [33].…”

“…Many researchers conducted heavy metal removal experiments using unmodified natural ligno-cellulosic biomaterials, and reported many positive results [4,7,8,11]. However, the application of unmodified lignocellulose has significant disadvantages such as low adsorption capacity in aqueous solution and high release of soluble organic compounds [5,12]. Accordingly, in recent years, there is an increasing tendency to modify lignocellulose-based biomaterials in order to improve the removal efficiency of heavy metals, remove soluble organic compounds, and remove dyes in aqueous solutions.…”

“…Lignocellulose has a three-dimensional aromatic structure and, when modified, has high reactivity, so a lot of interest has been focused on lignocellulose-based adsorbents [11,12].…”

“…In particular, several researchers have reported that sulfonation increases the adsorption efficiency of cationic heavy metals among chemical methods that can modify lignocellulose [14]. This is because pretreatment of lignocellulose using sulfonation leads to an increase in the negative charge, surface area and porosity of the biomass surface [10,12]. Similarly, Elangovan et al [15] reported that pretreatment of mangrove leaves and water lily leaves with sulfuric acid substantially improved the Cr(VI) adsorption capacity.…”