Person:
Monte Lara, María Concepción

First Name

María Concepción

Last Name

Monte Lara

URI

https://hdl.handle.net/20.500.14352/76231

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Químicas

Department

Ingeniería Química y de Materiales

Area

Ingeniería Química

Identifiers

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Search Results

Now showing 1 - 10 of 11

Extending the limits of paper recycling - improvements along the paper value chain
(Forest Systems, 2013) Blanco Suárez, María Ángeles; Miranda Carreño, Rubén; Monte Lara, María Concepción
Aim of study: The purpose of this study is to analyze how paper recycling activities in Europe can be extended through different improvements along the paper value chain. The importance of this study lies in the identification of the present barriers in paper recycling and how they can be overcome. Area of study: Europe. Material and methods: All the main stages along the paper value chain have been analyzed for possible improvements: collection of recovered paper (availability and quality), sorting of recovered paper, paper production, and printing and converting activities. Main results: To increase paper recycling in Europe the following improvements are necessary. First, it is mandatory to increase the availability of recovered paper through more efficient collection systems (avoiding the use of commingled collection systems) and limiting the competition with energy purposes and the exports. Second, it is necessary to extend sorting activities, which can be achieved by reducing sorting costs by the use of automatized sorting systems. Third, there is a need to increase the recyclability of paper products by the commitment of printing and converting industries to use recycling-friendly printing inks and adhesives. Finally, environmental awareness of the citizens is still an important driver for increasing recycling activities, affecting not only recovery but to all the stages along the paper recycling chain. Research highlights: Although the recycling rate in Europe is already very high (68.9%), there is still room to further extend paper recycling activities through different improvements along the paper value chain.
Comparison of ultrafiltration and dissolved air flotation efficiencies in industrial units during the papermaking process
(APPITA Journal, 2011) Monte Lara, María Concepción; Ordóñez Sanz, Ruth; Hermosilla Redondo, María Daphne; González Sánchez, Mónica; Blanco Suárez, María Ángeles
The efficiency of an ultrafiltration unit has been studied and compared with a dissolved air flotation system to get water with a suited quality to be reused in the process. The study was done at a paper mill producing light weight coated paper and newsprint paper from 100% recovered paper. Efficiency was analysed by removal of turbidity, cationic demand, total and dissolved chemical oxygen demand, hardness, sulphates and microstickies. Moreover, the performance of the ultrafiltration unit and the membranes were studied deeply, analysing its variability during the filtration process. As expected, the ultrafiltration gave higher removal efficiencies than the dissolved air flotation cell in parameters like turbidity, cationic demand, dissolved chemical oxygen demand and microstickies. The greatest difference in performance between the units concerned cationic demand and dissolved chemical oxygen demand. Ultrafiltration was influenced by the operating time, decreasing the removal efficiency of the dissolved fraction by 75% and of the colloidal fraction by 30% after 312 of running. Membrane autopsy, carried out to identify the cause of poor membrane performance, showed that the active layer was degraded due to the effect of suspended solids.
Improving deposition tester to study adherent deposits in papermaking
(Chemical Engineering Research and Design, 2012) Monte Lara, María Concepción; Sánchez, Mónica; Blanco Suárez, María Ángeles; Negro Álvarez, Carlos Manuel; Tijero Miquel, Julio Félix
Conventional methods used for the quantification of adherent material contained in a pulp suspension propose either filtration of the sample, which may lead to loss of sticky material in the filtrate, or dilution of the pulp, which may cause destabilization of the dissolved and colloidal material; thus, leading to unreliable results. In 1998, the Cellulose and Paper Group of University Complutense of Madrid developed a deposition tester which aimed to quantify the adherence of material (microstickies and secondary stickies from dissolved and colloidal material) that was present in white waters generated during papermaking processes. In this paper, an improved deposition tester capable of directly studying the deposition tendency of total stickies in pulps without dilution is described and validated. The design of this device prevents the rotor system from being clogged and blocked by pulps, hence, being able to quantify deposits without having to apply any filtration and/or dilution stages. In addition, the study provides determination of the equipment optimum operating conditions as well as comparison between the improved deposition tester and the one previously developed. Results show that this deposition tester can determine the adherent material contained in pulps with a consistency up to 1%. The comparison of results obtained after applying both deposition quantification methods shows that the quantities of deposits that were measured with the improved tester are slightly lower than those obtained with the application of the conventional method; however, they are in the same order of magnitude. Therefore, it is possible for the improved tester to determine total stickies in all cases, including cases that it is not convenient to apply a filtration and/or a dilution stage.
Time variations of macro and extractable stickies concentrations in deinking
(Industrial & Engineering Chemistry Research, 2010) McNeil, Donald; Miranda Carreño, Rubén; Monte Lara, María Concepción; Blanco Suárez, María Ángeles; Sundberg, Anna
The stickies content, both macrostickies and stickies extractable in a solvent, was determined for samples taken at short time intervals from deinking lines producing deinked pulp for newsprint production. The study was carried out at three mills on different continents, with each having a different source of recycled paper as raw material. The short-term variations in extractable stickies in the incoming raw material were quite extreme, with differences of 100% being seen within hours. Despite this, the final deinked pulp contained fewer sudden variations and with no correlation to the incoming stickies content. While the raw material appeared to affect the incoming stickies content, a well-optimised deinking line was able to buffer the raw material variability and the final stickies content was more dependent on the deinking process. This result was seen for the two mills examined for this phenomenon, despite a different raw material supply. Macrostickies were found to exhibit the same tendencies, although with smaller and less sudden variations. However, the variations of macrostickies and extractable stickies never correlated, even when both were measured for the same pulp fraction, thus confirming that solvent extraction is not an appropriate method for determination of macrostickies and is more a reflection of microstickies.
Enzymatic deinking of secondary fibers: cellulases/hemicellulases versus laccase-mediator system
(Journal of Industrial Microbiology & Biotechnology, 2012) Ibarra, David; Monte Lara, María Concepción; Blanco Suárez, María Ángeles; Martínez, Ángel ; Martínez, Maria Jesús
The use of enzymes has been suggested as an environmentally-friendly alternative to complement conventional chemical deinking in the recycling of recovered paper. This study compares the use of carbohydrate hydrolases versus laccase-mediator system for deinking printed fibers from newspapers and magazines. For this purpose, two commercial enzyme preparations with endoglucanase and endoxylanase activities (Viscozyme Wheat from Aspergillus oryzae and Ultraflo L from Humicola insolens) and a commercial laccase NS51002 from Trametes villosa), the latter in the presence of synthetic or natural (lignin related) mediators, were evaluated. The enzymatic treatments were studied at laboratory scale, using a standard chemical deinking sequence consisting of pulping, alkaline deinking and peroxide bleaching stages. Then, handsheets were prepared and their brightness, residual ink concentration, and strength properties were measured. Among the different enzymatic treatments assayed, both carbohydrate hydrolases were found to deink the secondary fibers more efficiently. Brightness increased up to 3-4% ISO on newspaper fibers, being Ultraflo 20% more efficient in the ink removal. Up to 2.5% ISO brightness increase was obtained when magazine fibers were used, being Viscozyme 9% more efficient in the ink removal. As regards laccase-mediator system, alone or combined with carbohydrate hydrolases, it was ineffective deinking both newspaper and magazine fibers, resulting in pulps with worse brightness and residual ink concentration values. However, pulp deinking by laccase-mediator system was displayed when secondary fibers rich in lignin, i.e. printed cardboard, were used, obtaining up to 3% ISO brightness increase and lower residual ink concentrations.
Morphological characterization of pulps to control paper properties
(Cellulose Chemistry and Technology, 2010) Moral, Ana; Monte Lara, María Concepción; Cabeza, Elena; Blanco Suárez, María Ángeles
Products at a high and constant level, for meeting the consumer demands. However, since paper recovery is increasing, the quality of recovered paper is decreasing and, what is even worse, it varies along the time. The physical properties of recycled pulp fibres have a strong influence on most of the paper properties and, therefore, they play an important role in the establishment of the optimal papermaking conditions. These properties are directly related to the morphology of fibres and to pulp composition. In recent years, several new fibre and pulp morphological analyzers have been developed and released on the market. The use of online optical fibre analyzers allows papermakers to know the variations in pulp quality, enabling them to adjust the process and to maintain constant the quality of the paper produced. However, most of these devices are optimized for virgin fibres, their application for recovered paper being still limited. The present paper describes the modifications carried out in the programs of a fibre and pulp morphological analyzer (Morfi V7.9.13.E) to optimize its performance for the characterization of recycled pulps. The three programs (VESSELS, FIBRES and SHIVES) that the device includes by default have been considered and validated in a paper mill, producing different grades of newsprint and light-weight coated papers. The results show that, with the modified program, the device appears as a very promising tool to control and improve the final quality of recycled paper.
Cellulose nanofibers and chitosan to remove flexographic inks from wastewaters
(Water research and technology, 2019) Balea Martín, Ana; Monte Lara, María Concepción; Fuente González, Elena De La; Negro Álvarez, Carlos Manuel; Sánchez Salvador, José Luis; Blanco Suárez, María Ángeles
Flexographic printing technology is an economical, productive, low maintenance and versatile technology. However, the removal of these inks by the traditional flotation process during paper recycling is not possible since they remain dissolved in the waters, making necessary the development of alternative methods. Recent studies have revealed the potential use of nanocellulose (NC) combined with a cationic polyacrylamide to remove flexographic inks from wastewater. The use of a natural polymer, such as chitosan, would be an important improvement of this treatment because NC and chitosan are the two most abundant natural polymers with interesting properties, such as non-toxicity and biodegradability. Therefore, in this study the decolorization of three flexographic inks (copper phthalocyanine blue, carbon black and diarylide yellow) by the sequential addition of cellulose nanofibers, produced from recycled paper, and chitosan has been evaluated. Results show that this eco-friendly approach has high potential for the removal of water-based inks with an almost 100% reduction of turbidity and ink from the wastewater. Moreover, the final sludge containing nanocellulose and inks could be used to reinforce the pulp of the middle layers of carton board, improving the mechanical properties of the product and reducing waste generation.
Effect of bleached eucalyptus and pine cellulose nanofibers on the physico-mechanical properties of cartonboard
(Bioresources, 2016) Balea Martín, Ana; Blanco Suárez, María Ángeles; Monte Lara, María Concepción; Merayo, Noemi; Negro Álvarez, Carlos Manuel
Extending the limits of paper recycling by increasing the number of recycling cycles results in decreased mechanical properties due to the irreversible hornification of cellulose fibers. This process alters the fiber structure and properties because of the repeated chemical and mechanical treatments that occur during wetting and drying. As a result, poor tensile strength is the main source of customer complaints to paper manufacturers. Cellulose nanofibers (CNF) from bleached eucalyptus and pine pulps were investigated as potential strength additives because of their proven contribution to interfiber bonding. These results were compared to the results obtained using different families of strength additives. The effects on the mechanical properties of recycled old corrugated containers were studied by measuring bursting, tensile, and short span compressive strength. Cellulose nanofibers and cationic polyacrylamide (cPAM) improved the mechanical strength properties when they were added at doses around 4 wt.%. A combination of CNF and cPAM was also tested. The effects of the combined additives were not as high as expected compared to the results achieved individually. The CNF from pine pulp resulted in the highest increase in bursting index when combined with cPAM, achieving an increase of over 93%. The combination of CNF from eucalyptus pulp and cPAM increased the bursting index over 60%.
Application of cellulose nanofibers to remove water-based flexographic inks from wastewaters
(Environmental Science and Pollution Research, 2017) Balea Martín, Ana; Monte Lara, María Concepción; Fuente González, Elena De La; Negro Álvarez, Carlos Manuel; Blanco Suárez, María Ángeles
Water-based or flexographic inks in paper and plastic industries are more environmentally favourable than organic solvent-based inks. However, their use also creates new challenges because they remain dissolved in water and alter the recycling process. Conventional deinking technologies such as flotation processes do not effectively remove them. Adsorption, coagulation/flocculation, biological and membrane processes are either expensive or have negative health impacts, making the development of alternative methods necessary. Cellulose nanofibers (CNF) are biodegradable, and their structural and mechanical properties are useful for wastewater treatment. TEMPO-oxidised CNF have been evaluated for the decolourisation of wastewaters that contained copper phthalocyanine blue, carbon black and diarlyide yellow pigments. CNF in combination with a cationic polyacrylamide (cPAM) has also been tested. Jar-test methodology was used to evaluate the efficiency of the different treatments and cationic/anionic demand, turbidity and ink concentration in waters were measured. Results show that dual-component system for ink removal has a high potential as an alternative bio-based adsorbent for the removal of water-based inks. In addition, experiments varying CNF and cPAM concentrations were performed to optimise the ink-removal process. Ink concentration reductions of 100%, 87.5% and 83.3% were achieved for copper phthalocyanine blue, carbon black and diarlyide yellow pigments, respectively. Flocculation studies carried out show the decolourisation mechanism during the dual-component treatment of wastewaters containing waterbased inks.
Nanocellulose characterization challenges
(Bioresources, 2021) Balea Martín, Ana; Blanco Suárez, María Ángeles; Delgado-Aguilar, Marc; Monte Lara, María Concepción; Tarrés, Quim; Fuente González, Elena De La; Mutjé, Per; Negro Álvarez, Carlos Manuel
Despite the extraordinary properties of nanocellulose (NC), as confirmed through two decades of exhaustive research, addressing an array of potential applications, the NC market is still far from reaching its full potential. Among the main causes is the lack of process-adapted measuring tools capable of characterizing NC, at acceptable speed and reliability, to meet the industrial demands in a cost-effective way. Therefore, reliable characterization methodologies of NC and new standards are of paramount importance in ensuring reproducible research results and quality control specifications for present and future NC products and applications. Furthermore, the successful industrial use of NC products depends on critical parameters that are still being identified and studied. This review paper aims to identify some of the current drawbacks and limitations in NC characterization that hinder their commercial deployment. Moreover, important challenges related to characterization and new opportunities for future research in this field are addressed.