Synthesis And Antibacterial Activity Of Copper Complex With Carboxymethyl Cellulose Based On Furfural Residue As Chelating Agent

In this paper, carboxymethyl cellulose （CMC） was synthesized using cellulose extractedfrom furfural residue;Then CMC was coordinated with copper chloride; At last, the structureand properities of copper complex was characterization and investigated.Firstly, cellulose was extracted and bleached by means of Milox method combined withalkaline hydrogen peroxide bleaching process. The influences of dosage of formic acid andhydrogen peroxide and other factors on the cellulose extraction effect were studied throughsingle factor experiments. Under the optimal conditions, the content of cellulose in the crudefiber was85.09%and the lignin content was3.22%. While the content of cellulose in theproduct was89.72%and lignin content was1.72%under the optimum bleaching conditions.The refined cellulose was characterized by FT-IR, XRD and CP/MAS¹³C NMR. XRDshowed the extracted cellulose was typeⅠ,while¹³C NMR spectra showed crystalline areaand amorphous area of the cellulose. Thermal stability analysis proved its decompositiontemperature range was from220to350℃and the maximum decomposition rate appeared at317℃.Secondly, sodium carboxymethyl cellulose was prepared from refined cellulose in thesolvent of isopropanol. In this process, NaOH was used as basifying agent and chloroaceticas etherifying agent. NaOH dosage, chloroacetic acid dosage and other factors on degree ofsubstitution of the synthesized carboxymethyl cellulose were studied through orthogonalexperiments.The results revealed that the amount of NaOH is the vital factor, next is thetemperature, the amount of monochloroacetic acid and time are less important. Sodiumcarboxymethyl cellulose obtained under the optimal conditions had a degree of substitutionof0.96and purity of86%, its viscosity was40mPa·s in1%aqueous solution at25℃. Thestructure of prepared sodium carboxymethyl cellulose was characterized via FT-IR, XRD,CP/MAS¹³CNMR et al. The carboxymethylation reaction was confirmed by comparing ofspectrum with raw cellulose. The thermal analysis data indicated that the obtained sodiumcarboxymethyl cellulose had a decomposition temperature range of220to330℃, thedecomposition rate was maximum at temperature of280℃.Finally, copper chloride was coordinated by the sodium carboxymethyl cellulose. Thestructure and properities of the synthesized complexes were characterized by FT-IR, XRD,CP/MAS¹³C NMR, thermal analysis, elemental analysis, atomic absorption and other means,indicating a possible formula [Cu （CMC）Cl]_n. The thermal stability results showed that the complexes had a decomposition temperature range of180to260℃, the decomposition ratewas maximum at220℃. The antimicrobial properties of the complexes were measured bythe methods of the inhibition zone and the minimum inhibitory concentration. The resultsimproved that the complexes had rejection capability against Gram-negative bacteria E. coli,the Gram-positive bacterium Staphylococcus aureus, Penicillium and Aspergillus niger. Theminimum inhibitory concentration （MIC） of the complexes was0.004g/mL for eitherbacteria or fungi. Water-solubility and washability experiments demonstrated that the Cu2+inthe prepared copper coordination complexes presented favorable washability and did not loseeasily with water.