Structural Study of Silver-modified Powder Lignocellulose by Computer Simulation of Atomic Structure

Abstract

Objective: In the present work we set ourselves the following tasks: to perform a comparative XRD study of samples of the powder lignocellulose isolated from hardwood pulp and the same samples containing embedded silver and also to perform a computer-aided construction of an atomic con-figuration that describes the structure of the silver-modified cellulose. Methods: The structure of silver-modified powder cellulose isolated from hardwood lignocellu-lose was studied by X-ray structural analysis and computer simulation. Results and Discussion: A full-profile analysis showed that the studied sample belongs to the monoclinic phase of cellulose Iβ with an antiparallel arrangement of molecules, with the unit cell lattice parameters a = 7.881 Å, b = 7.837 Å, c = 10.603 Å, γ = 95.63°, and volume V = 652 ų. The sizes of the coherent scattering regions (CSRs) of the sample were calculated by the Scherrer equation and used to analyze the supramo-lecular structure. An increase in the CSR in the [100] direction and a decrease in the CSR in the [001] direction compared to the respective parameters of powder lignocellulose were observed. The cross-sectional area of the fibril of the modified sample in the ab plane (980 Ų) was found to be ~8% larger than that of powder cellulose. The crystallinity index (CI) calculated by the Ruland method estimated at 79% which was 7% higher than that of powder cellulose. Conclusions: The final cluster formula of the silver-modified powder cellulose was determined as C₆O₅H_10.12Ag_0.08.