288 research outputs found
Food By-Product Valorization by Using Plant-Based Coagulants Combined with AOPs for Agro-Industrial Wastewater Treatment
Re-using and adding value to by-products is one of the current focuses of the agri-food
industry, following the Sustainable Development Goals of United Nations. In this work, the byproducts
of four plants, namely chestnut burr, acorn peel, olive leaf, and grape stem were used as
coagulants to treat elderberry wastewater (EW), a problematic liquid effluent. EW pre-treatment using
these natural coagulants showed promising results after pH and coagulant dosage optimization.
However, the decrease in total organic carbon (TOC) was not significant, due to the addition of
the plant-based natural coagulants which contain carbon content. After this pre-treatment, the
photo-Fenton advanced oxidation process was selected, after preliminary assays, to improve the
global performance of the EW treatment. Photo-Fenton was also optimized for the parameters of
pH, H2O2, Fe2+, and irradiance power, and the best conditions were applied to the EW treatment.
Under the best operational conditions defined in the parametric study, the combined results of
coagulation–flocculation–decantation (CFD) and photo-Fenton for chestnut burr, acorn peel, olive
leaf, and grape stem were, respectively, 90.2, 89.5, 91.5, and 88.7% for TOC removal; 88.7, 82.0, 90.2
and 93.1%, respectively, for turbidity removal; and finally, 40.6, 42.2, 45.3, and 39.1%, respectively, for
TSS removal. As a final remark, it is possible to suggest that plant-based coagulants, combined with
photo-Fenton, can be a promising strategy for EW treatment that simultaneously enables valorization
by adding value back to food by-productsinfo:eu-repo/semantics/publishedVersio
Rotational Surfaces in and Solutions in the Nonlinear Sigma Model
The Gauss map of non-degenerate surfaces in the three-dimensional Minkowski
space are viewed as dynamical fields of the two-dimensional O(2,1) Nonlinear
Sigma Model. In this setting, the moduli space of solutions with rotational
symmetry is completely determined. Essentially, the solutions are warped
products of orbits of the 1-dimensional groups of isometries and elastic curves
in either a de Sitter plane, a hyperbolic plane or an anti de Sitter plane. The
main tools are the equivalence of the two-dimensional O(2,1) Nonlinear Sigma
Model and the Willmore problem, and the description of the surfaces with
rotational symmetry. A complete classification of such surfaces is obtained in
this paper. Indeed, a huge new family of Lorentzian rotational surfaces with a
space-like axis is presented. The description of this new class of surfaces is
based on a technique of surgery and a gluing process, which is illustrated by
an algorithm.Comment: PACS: 11.10.Lm; 11.10.Ef; 11.15.-q; 11.30.-j; 02.30.-f; 02.40.-k. 45
pages, 11 figure
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