Chemical Modeling of Acid-Base Properties of Soluble Biopolymers Derived from Municipal Waste Treatment Materials

Abstract

This work reports a study of the proton-binding capacity of biopolymers obtained from different materials supplied by a municipal biowaste treatment plant located in Northern Italy. One material was the anaerobic fermentation digestate of the urban wastes organic humid fraction. The others were the compost of home and public gardening residues and the compost of the mix of the above residues, digestate and sewage sludge. These materials were hydrolyzed under alkaline conditions to yield the biopolymers by saponification. The biopolymers were characterized by 13C NMR spectroscopy, elemental analysis and potentiometric titration. The titration data were elaborated to attain chemical models for interpretation of the proton-binding capacity of the biopolymers obtaining the acidic sites concentrations and their protonation constants. The results obtained with the models and by NMR spectroscopy were elaborated together in order to better characterize the nature of the macromolecules. The chemical nature of the biopolymers was found dependent upon the nature of the sourcing materials.

A Low-Cost Ecofriendly Oxidation Process to Manufacture High-Performance Polymeric Biosurfactants Derived from Municipal Biowaste

“…SBP was available from previous work [ 10 , 11 ]. It was obtained via hydrolysis at pH 13 and 60 °C from the anaerobic digestate of unsorted municipal food waste.…”

“…In the above context, several papers have been published [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ] on the properties and performance of new soluble polymeric biosurfactants obtained by hydrolysis and oxidation of collected and fermented municipal biowaste (MBW).…”

“…The product obtained by hydrolysis of the MBW anaerobic digestate was characterized by a surface tension (γ) of 49 mN/m at 1 g/L concentration in water compared to γ 61–63 mN/m at 2–3 g/L for the hydrolysates of three different MBW composts [ 10 , 11 ]. The product obtained by hydrolysis of the MBW anaerobic digestate was further processed by oxidation in plain water in the presence and absence of added hydrogen peroxide at 0.1–3 H 2 O 2 moles per mole of organic C contained in the pristine digestate and in the presence or absence of irradiation with simulated solar light [ 17 ].…”

“…The development of high-performance biosurfactants is an integral part of a wider research framework aiming to develop biorefineries for the production of new value-added chemical specialties from renewable feedstock [ 18 , 19 ]. The production of biosurfactants from MBW, as described in the above cited work [ 10 , 11 , 12 , 13 , 14 , 16 , 17 ] has, in principle, several advantages arising from the nature of the material used as feedstock and from the fermentation and/or chemical processes adopted. First, MBW is the most available negative cost feedstock produced worldwide [ 16 ].…”

Pigs’ Husbandry as Case Study to Test Effects of Vegetable Residues’ Hydrolysates on Animals

“…The SBO are composed by a heterogeneous pool of macromolecules with 67-463 kg·mol −1 molecular weight and 6-53 polydispersity index. They contain aliphatic and aromatic C chains substituted by a wide variety of acid and basic functional groups of different strength (Tabasso et al, 2015). Their chemical nature bears chemical similarities with natural humic substances (HS).…”