Poster
Abstract
Research summary supplied by the authors
This study was carried out within the MICS (Made in Italy–Circular and Sustainable) Extended Partnership and received funding from the European Union Next-Generation EU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.3 –D.D. 1551.11-10-2022, PE00000004). This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them NIR spectroscopy is a non-destructive analytical technique that analyses molecular vibrations—mainly C-H, O-H, and N-H bonds—through light-matter interaction in the near-infrared region. It is especially suited for studying organic and biological materials. Near Infrared Multivariate Chemometric Models Chemometrics combines statistical and mathematical tools to extract relevant information from spectroscopic data. Principal Component Analysis (PCA) is used to reduce data dimensionality, detect hidden patterns, and identify outliers by projecting spectra into a lower-dimensional space that retains most of the original variance. Partial Least Squares Regression (PLSR) enables the development of predictive models correlating NIR spectra with key chemical and physical properties, supporting real-time process monitoring. To assess the discriminating power of NIR-based chemometrics, leather samples processed with different tanning methods (traditional and innovative) were analysed. PCA (Principal Component Analysis) was used to reduce spectral data dimensionality and highlight chemical and structural differences. This microNIR–PCA workflow robustly differentiate industrial tanning systems, even accounting for natural biological variability, and confirms its value for real-time classification and quality control. PCA Differentiation of Tanning Methods PLSR Quantification of Tanning Agents Partial Least Squares Regression (PLSR) was used to develop quantitative models capable of estimating the concentration of tanning agents in aqueous phase. Models were built using standard solutions under controlled conditions to simulate the actual tanning process. Results showed good predictive accuracy, highlighting the potential of PLSR for real-time quality control. Score plots were used to visualize sample distribution in principal component space. Loading plots identified key wavelengths influencing the prediction of chemical parameters. Mimosa Chrome Sintans Zeolites Product and Process Control Adsorbing Cr(III) - based tanning agents via zeolites Primary analytical analysis using ICP - OES Secondary analysis on powders and water via NIR Direct analysis via NIR The application of NIR spectroscopy combined with PLSR modelling enabled the quantitative evaluation of chromium removal from aqueous solutions using innovative adsorbent materials such as zeolites. Removal rates of up to 89% within 8 hours and 99% after 24 hours PLSR Quantification Chrome removal Conclusion NIR spectroscopy combined with PCA and PLSR proved to be an effective, non-destructive tool for monitoring leather tanning processes. The methods allowed: •Discrimination between traditional and innovative tanning systems. •Real-time estimation of tanning agent concentrations. •Evaluation of chromium removal using zeolites. These results support the use of NIR-chemometric approaches for quality control and sustainability in the tanning industry. Future work will focus on model expansion, in-line monitoring, and integration of advanced data analysis techniques.