Łukasz Klapiszewski

Modification of Chitin with Kraft Lignin and Development of New Biosorbents for Removal of Cadmium(II) and Nickel(II) Ions

Novel, functional materials based on chitin of marine origin and lignin were prepared. The synthesized materials were subjected to physicochemical, dispersive-morphological and electrokinetic analysis. The results confirm the effectiveness of the proposed method of synthesis of functional chitin/lignin materials. Mechanism of chitin modification by lignin is based on formation of hydrogen bonds between chitin and lignin. Additionally, the chitin/lignin materials were studied from the perspective of waste water treatment. The synthetic method presented in this work shows an attractive and facile route for producing low-cost chitin/lignin biosorbents with high efficiency of nickel and cadmium adsorption (88.0% and 98.4%, respectively). The discovery of this facile method of synthesis of functional chitin/lignin materials will also have a significant impact on the problematic issue of the utilization of chitinous waste from the seafood industry, as well as lignin by-products from the pulp and paper industry.

Physicochemical and electrokinetic properties of silica/lignin biocomposites

A new method of synthesis of novel composites obtained from silica and Kraft lignin has been proposed. Silica used in the study was obtained by three methods (hydrolysis and condensation of tetraethoxysilane, precipitation in a nonpolar and polar medium with the use of sodium silicate). To extend the possible range of applications, the silica was preliminary modified with N-2-(aminoethyl)-3-aminopropyltrimethoxsysilane, and finally it was modified with Kraft lignin earlier oxidised with sodium periodate (lignin bonded to SiO2 by covalent interactions). The products physicochemical and electrokinetic properties were thoroughly analysed. The dispersive properties and surface morphology were evaluated on the basis of particle size distributions and SEM images. The stability of dispersion in inorganic-organic systems were characterised on the basis of the zeta potential, whose value also permitted concluding on the interactions between colloidal molecules dispersed in water solutions. The products were subjected to elemental analysis to get percentage contents of N, C, H, S elements and were also characterised by XPS and FT-IR spectroscopy. Results of the study are of practical importance in prospective applications of SiO2/lignin biocomposites.

An extreme biomimetic approach: hydrothermal synthesis of β-chitin/ZnO nanostructured composites

β-Chitinous scaffolds isolated from the skeleton of marine cephalopod Sepia officinalis were used as a template for the in vitro formation of ZnO under conditions (70 °C) which are extreme for biological materials. Novel β-chitin/ZnO film-like composites were prepared for the first time by hydrothermal synthesis, and were thoroughly characterized using numerous analytical methods including Raman spectroscopy, HR-TEM and XRD. We demonstrate the growth of hexagonal ZnO nanocrystals on the β-chitin substrate. Our chitin/ZnO composites presented in this work show antibacterial properties against Gram positive bacteria and can be employed for development of inorganic-organic wound dressing materials.

Kraft lignin and silica as precursors of advanced composite materials and electroactive blends

In this study, advanced multifunctional silica/lignin composite materials have been prepared. The main focus of this study includes the chemical modification of Kraft lignin, and its interaction with silica matrix, thereby providing the possibility of applying the obtained systems in a number of areas, including electrochemistry. Analysis of dispersive–morphological properties revealed that the samples containing 10–20 parts by weight of lignin had the best parameters. The elemental analysis of the final composites, thus, obtained indicated an increase in the contents of carbon, hydrogen and sulphur with increasing quantity of lignin used. Spectrophotometric evaluation of the products obtained, proves the successful synthesis of silica/lignin composites which is manifested by the presence of characteristic bands of appropriate functional groups. The increasing intensity of these bands with increasing content of lignin in the silica matrix conforms entirely with the expectations. Thus, obtained composite powders were blended with multiwalled carbon nanotubes at the mass ratio of 1:2 with the aid of ultrasound. The blends were cast-deposited on glassy carbon electrode and the electrochemical activity was assessed by cyclic voltammetry. It revealed the presence of a redox system assigned to lignin-derived quinone/hydroquinone couple.

Chitin-Lignin Material as a Novel Matrix for Enzyme Immobilization

Innovative materials were made via the combination of chitin and lignin, and the immobilization of lipase from Aspergillus niger. Analysis by techniques including FTIR, XPS and 13C CP MAS NMR confirmed the effective immobilization of the enzyme on the surface of the composite support. The electrokinetic properties of the resulting systems were also determined. Results obtained from elemental analysis and by the Bradford method enabled the determination of optimum parameters for the immobilization process. Based on the hydrolysis reaction of para-nitrophenyl palmitate, a determination was made of the catalytic activity, thermal and pH stability, and reusability. The systems with immobilized enzymes were found to have a hydrolytic activity of 5.72 mU, and increased thermal and pH stability compared with the native lipase. The products were also shown to retain approximately 80% of their initial catalytic activity, even after 20 reaction cycles. The immobilization process, using a cheap, non-toxic matrix of natural origin, leads to systems with potential applications in wastewater remediation processes and in biosensors.

Kraft lignin/silica-AgNPs as a functional material with antibacterial activity.

Advanced functional silica/lignin hybrid materials, modified with nanosilver, were obtained. The commercial silica Syloid 244 was used, modified with N-(2-aminoethyl)-3-aminopropyltrimethoxysilane to increase its chemical affinity to lignin. Similarly, kraft lignin was oxidized using a solution of sodium periodate to activate appropriate functional groups on its surface. Silver nanoparticles were grafted onto the resulting silica/lignin hybrids. The systems obtained were comprehensively tested using available techniques and methods, including transmission electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, elemental analysis and atomic absorption spectroscopy. An evaluation was also made of the electrokinetic stability of the systems with and without silver nanoparticles. Conclusions were drawn concerning the chemical nature of the bonds between the precursors and the effectiveness of the method of binding nanosilver to the hybrid materials. The antimicrobial activity of the studied materials was tested against five species of Gram-positive and Gram-negative bacteria. The addition of silver nanoparticles to the silica/lignin hybrids led to inhibition of the growth of the analyzed bacteria. The best results were obtained against Pseudomonas aeruginosa, a dangerous human pathogen.

Preparation and characterization of multifunctional chitin/lignin materials

Multifunctional chitin/lignin materials were synthesized. In order to combine mechanical milling of the biopolymers with simultaneous mixing, a centrifugal ball mill was utilized. The resulting materials, differing in terms of the proportions of precursors used, underwent detailed physicochemical and dispersive-morphological analysis. On the basis of FT-IR spectra and results of elemental analysis, the efficiency of the preparation of the materials was determined. The influence of the precursors on the thermal stability of the resulting systems was also evaluated. Zeta potential was determined as a function of pH to describe the electrokinetic stability of aqueous dispersions. This is important for evaluating the utility of the materials and indirectly confirms the effectiveness of the proposed method of synthesis of chitin/lignin products. Measurements were performed to determine basic colorimetric parameters, crucial in the production technology of multiple colored materials. It is expected that chitin/lignin materials will find a wide range of applications (biosorbents, polymer fillers, and electrochemical sensors), as they combine the unique properties of chitin with the specific structural features of lignin to provide a multifunctional material.

Silica synthesis by the sol-gel method and its use in the preparation of multifunctional biocomposites

AbstractThis study focuses on the optimization process of silica synthesis using the sol-gel method while applying a statistical design of experiments which was based on a multilevel mathematical model. The product obtained in the process of optimized synthesis, characterized by the best dispersive and morphological parameters, was used for the preparation of organic/inorganic composites. The organic precursor was Kraft lignin, a high-molecular natural polymer. Synthesis of silica/lignin biocomposites was carried out by three proposed methods. The physicochemical properties and dispersive-morphological properties of each product were determined using the following available methods: Scanning Electron Microscopy — SEM, Non-Invasive Back-Scattering — NIBS, Fourier Transform Infrared Spectroscopy — FT-IR, Thermogravimetric analysis — TG and others. The electrokinetic and thermal properties of the biocomposites sufficed to be applied for example, as a cheap and biodegradable polymer filler. Further areas of application of these composites were sought, especially in electrochemistry as the advanced electrode materials.

Treatment of model and galvanic waste solutions of copper(II) ions using a lignin/inorganic oxide hybrid as an effective sorbent

A study was made concerning the removal of copper(II) ions from model and galvanic waste solutions using a new sorption material consisting of lignin in combination with an inorganic oxide system. Specific physicochemical properties of the material resulted from combining the activity of the functional groups present in the structure of lignin with the high surface area of the synthesized oxide system (585m2/g). Analysis of the porous structure parameters, particle size and morphology, elemental composition and characteristic functional groups confirmed the effective synthesis of the new type of sorbent. A key element of the study was a series of tests of adsorption of copper(II) ions from model solutions. It was determined how the efficiency of the adsorption process was affected by the process time, mass of sorbent, concentration of adsorbate, pH and temperature. Potential regeneration of adsorbent, which provides the possibility of its reusing and recovering the adsorbed copper, was also analyzed. The sorption capacity of the material was measured (83.98mg/g), and the entire process was described using appropriate kinetic models. The results were applied to the design of a further series of adsorption tests, carried out on solutions of real sewage from a galvanizing plant.

Silica/lignosulfonate hybrid materials: Preparation and characterization

The research reported here concerns the synthesis, characterization and potential applications of silica/lignosulfonate hybrid materials. Three types of silica were used (Aerosil®200, Syloid®244 and hydrated silica), along with magnesium lignosulfonate. The effectiveness of the hybrid material synthesis methodology was confirmed indirectly, using Fourier transform infrared spectroscopy, elemental and colorimetric analysis. Dispersive-morphological analysis indicates that the products with the best properties were obtained using 10 parts by weight of magnesium lignosulfonate per 100 parts of Syloid®244 silica. The relatively high thermal stability recorded for the majority of the synthesized products indicates the potential use of this kind of a material as a polymer filler. Results indicating the high electrokinetic stability of the materials are also of great importance. Additionally, the very good porous structure properties indicate the potential use of silica/lignosulfonate systems as biosorbents of hazardous metal ions and harmful organic compounds.