Isolating cellulose from wood-based residues by Hindi-Fenton reaction

Several scientists have used Fenton reaction to oxidize contaminants, but no one has generated its exothermic reaction as an energy sink supply. The released heat can be used for performing another reaction such as delignification of woody tissue, synthesis of microcrystalline cellulose or preparing noble metal nanocrystals. Accordingly, there is no need for using external heat provider. The reaction’s efficiency is dependent on temperature, reagents’ concentration, pH and time. No chemists were noticed that this efficiency is independent on materials’ reaction vessels containing the chemical reagents. It was noticed that the Fenton reaction take more than one hour to be performed when glassware was used, while few minutes when stainless teal backbone’s reaction vessel. This phenomenon was noticed, performed by the stainless-steel body of the reactor vessel. This was illustrated by that the stainless steel acted as an electron donation which synergized the Fenton reagents (H2O2 + Fe-salt + citric acid) for any chemical reactions.
This is the first time that citric acid is used as a member of a delignification reagent
system for lignocellulosic materials. Citric acid is well known for its ability as a swelling reagent for cellulosic fibers enhancing the oxidation process for lignin, some extractives, hemicelluloses, and some other residues, leading to the obtainment of pure α-cellulose. This process was performed with a liquid-to-solid ratio of 15/1 at a temperature of 70 ◦C, which can be obtained via electric heating coils or with flat-plate solar collectors. Moreover, this moderate temperature can be easily reached using the modified Fenton-like reaction [23].
It is worth mentioning thatH2O2 was used in the present study in two different reagent systems: the 1st system comprises H2O2/citric acid (2% wt/wt and 5%, respectively) for the delignification process contacting the lignocellulosic materials, while the 2nd system (depending on the Fenton-like reaction) including high concentrations of H2O2/citric acid (20% wt/wt and 20%, respectively) synergized with iron atoms (emitted from steel rods) for generating exothermic heat. As a result of the above-mentioned 2nd reagent system, the heat released from the Fenton reaction can be used to achieve another chemical reaction [Table S4] without needing electric coils [23]. It must be understood that the 2nd reagent system, with its high concentrations of H2O2 and citric acid, does not contact the lignocellulosic materials, but it is circulated in a separate closed loop surrounding the reaction vessel.
The present project is related to a novel thermal machine that able to generate continuous energy needed for all industrial processes in a safe manner (Fenton apparatus-granted patent). Accordingly, there is no need for using heating coils that are perishable and consume high electric energy. In addition, this technique uses a novel stirring (agitation) process (granted patent) for the entire precursors using various gases instead of using metalic stirrers which are susceptible for corrosion. The energy generated by the 1st invention arose from reacting citric acid with hydrogen peroxide in presence of iron atoms. Accordingly, a novel device will be invented to synthesis of hydrogen peroxide depending on the solar electrolysis of water.