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The primary aim of this study is to determine the effectiveness of separating ink particles which are adherent to cellulose fibers from cellulose fibers after recycling. In addition, after recyclin...

The deinking effect of printing paper filled with CaSiO3 and CaSiO3/French chalk was investigated. As a result, it shows that the two kinds of paper samples have better deinking effect, and the whiteness of the former is slightly higher than that of the latter. However, the strength index of the former is slightly lower than that of the latter. The adhesive removal effect of the paper sample filled with CaSiO3 is better than that of the paper filled with CaSiO3/ French chalk powder.

The potential of alkaline cellulo-xylanolytic enzymes from non-pathogenic Bacillus subtilis strain was tested for deinking of photocopier waste paper. Cellulase and xylanase play a crucial role in deinking of different types of waste paper. Partial purification of cellulo-xylanolytic enzymes was carried out using ultrafiltration followed by ammonium sulfate precipitation. The ultrafiltered enzyme was used for deinking the photocopier waste paper along with chemical deinking. An enzyme dose of 0.6 IU/g and reaction time of 60 min for ultrafiltered cellulo-xylanolytic enzyme significantly increased deinking efficiency, tear index (9.52%) and folding endurance (5±2%) as compared to chemical deinking. There was improvement in strength properties such as tear index and double-fold along with freeness of pulp (18%). There was slight decrease in tensile index (0.6%) and burst index (16%) while ISO brightness remained unaffected. Enzymatic deinking (74.3%) by ultrafiltered cellulo-xylanolytic from Bacillus subtilis was found significant over conventional chemical deinking.

© 2022, Publishing House of the Romanian Academy. All rights reserved.This study aimed to determine whether 100% recycled papers can replace papers made from virgin fibers for the purpose of electrophotographic printing for packaging by evaluating the recycling potential of electrophotographically printed paper using the INGEDE and the washing deinking method. In the first part of the study, typical office copy paper, containing up to 30% recycled fiber, was printed electrophotographically. In the second part of the study, the deinked pulp was then used to prepare the handsheets for deinking evaluation, paper analysis and printability analysis. The print quality of the recycled papers was highly encouraging, as the results were comparable and, in some cases, identical to those of papers manufactured from virgin fibers.

An alkaliphilic Mucor circinelloides WSSDBS2F1 strain, with the ability to produce endoglucanase and exoglucanase enzymes, was isolated from decomposing bagasse, originating from a sugar processing mill in Punjab, India, and then screened. A pH range of 7-11, temperature of 30-60 °C, incubation period of 4-12 days, different lignocellulosic waste and nitrogen sources were investigated for optimum production of cellulase enzyme. Response Surface Methodology (RSM) was the statistical tool used for optimization of endoglucanase and exoglucanase production, following the one-factor-at-a-time approach. The optimized endoglucanase was further evaluated for its ability to deink waste paper, compared to chemical deinking. It was found that the enzymatically deinked pulp had high ISO brightness, tensile, burst and tearing strength, as compared to chemically deinked and control pulps. Scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR) were also used to confirm the action of the endoglucanase enzyme on waste paper.

Measurements of bubble size distributions are very important in flotation which is widely used in different chemical industries such as the recovery of valuable minerals, wastewater treatment, deinking of waste paper, and oil recovery from tar sands. Although numerous authors determined bubble size distributions (BSD-s) in gas–liquid systems, BSD-s have been rarely determined in gas–liquid–solid systems. Moreover, the influence of BSD-s on flotation has not been quantified under a wide range of experimental conditions. Thus, this paper is focused on measurements of bubble size distributions by changing surfactant dosage, solid percentage, air velocity and particle size as well as establishing the relationships between bubble size distribution properties and flotation performances. It was found that the experimental bubble size distributions are successfully fitted by using the log-normal distribution model in which the two model parameters (μ and σ) are used. The results showed that the most important factors affecting the Sauter mean diameter (d32), the model parameters and the flotation recoveries are the surfactant dosage and the solid percentage. The increase in the surfactant dosage decreased d32 probably due to the decrease in liquid surface tension. The increase in solid percentage resulted in an increase in d32 perhaps due to the increase in the pulp viscosity at high solid percentage. The lower the d32, the lower the flotation recovery. The results show that d32 and the model parameters represent the true BSD-s. However, a thorough understanding of bubble size distributions is needed to better understand flotation performances.

Three approaches were examined for the reutilization of cold caustic extraction (CCE) lye. The term CCE lye refers here to the used NaOH solution with relatively high alkali content, which could be wasted if not reused properly. The results showed that CCE lye can be effectively applied in deinking, alkaline hydrogen peroxide bleaching, and oxygen delignification processes. The CCE lye improved the physical strength of the dried sheet of pulp, as the tensile index increased by 17.9% to 40.5%, the tear index increased by 2.9% to 22.2%, and the burst index increased by 10.5% to 41.0%. The results demonstrated the feasibility of integrating the CCE process of dissolving pulp production with regular pulping and bleaching processes.

In traditional deinking process, large amounts of chemicals are required which makes these methods expensive and polluting. Also, application of sustainable material implies the use of green processes to reduce waste and pollution. Green enzymatic deinking processes are alternatives to those technologies that have negative effects on the environment. In this work, we applied response surface methodology for deinking the electrophotography-printed paper based on a systematic experimental pattern. The individual and interactive effects of enzymatic deinking parameters including time, temperature, and enzyme dosage on the handsheet properties were investigated. Different analyses were carried out to determine the best process conditions of enzymatic deinking to optimize the handsheet properties (i.e., tensile, burst, whiteness, and brightness). The obtained responses of an oven-dried fiber at 45 min, 43 °C and the enzyme concentration of 1 mg/15 g were 12.44, 0.65, 72.20, and 87 for tensile strength, burst strength, whiteness, and brightness, respectively. Measuring the optical density of the deinked handset after printing showed that the printability of the deinked paper is in the desired range.

Virgin pulp is made by splitting up cellulose fibers from the woods by mechanical and chemical process without adding any recycled pulp content. The demand for trees, which are the basic raw material for making virgin pulp, increasing constantly in enormously growing paper manufacturing industry. The paper, which is made from virgin pulp is called as virgin paper and this is considered as better quality paper than the recycled paper. Now there is a need to increase the quality of recycled paper to equalize the quality of virgin paper, to reduce the demand for trees to make virgin pulp. In recycling, dispersive system is responsible for the de-inking process, which is one of the pulp purifying process which removes the printing ink from fibers. Chemicals are added in this deinking process which causes a serious problem by increasing the chemical concentration level of industrial outlet water. In conventional deinking technology, dispersive system is controlled by DCS which is quite complicated to control complex loop of operations. To overcome these problems, the dispersive system operations are controlled by PLC along with sensors which make the process easier and replacing the chemicals with enzymes will reduce the chemical concentration level of industrial outlet water and increases the quality of paper.

Paper recycling for producing a new paper that can be used from old spent paper has gained increased interest, and this process helps prevent the paper from accumulating in landfills, reducing pollution and greenhouse gas emissions. In this work old newspaper (ONP) supplied from Al-Ahram Press is de-inked by washing process using sodium hydroxide, surfactant then hydrogen peroxide was applied to bleach the recycled deinked ONP. Following single-stage bleaching, the fiber properties of the pulp (brightness, tensile, tear strength, and burst index) were determined. The Effect of hydrogen peroxide dose, consistency, and temperature on the pulp brightness were studied. The deinking step produces deinked pulp with low brightness 51.75% ISO and the single-stage peroxide bleaching applied to the deinked ONP pulp could produce pulp with brightness 64.05% ISO at 60 min, 80°C, H2O2 concentration 2% and consistency 20%. The obtained data showed that the brightness of the deinked ONP increases with increasing hydrogen peroxide dose, consistency, and temperature. Also, it was found that the tensile strength and burst index increase by increasing brightness while, tear strength decreased.

There is an urgent need to close the loop of plastic waste. One of the main challenges towards plastic packaging waste recycling is the presence of a variety of contaminants. These contaminants include organic residues, additives, labels, inks and also other plastic types that can be present in the waste stream due to missorting or in multimaterial structures (e.g. multilayer films in packaging). In this context, pre-treatment processes are a promising route to tackle the difficulties that are encountered in mechanical and chemical recycling due to these contaminants. This chapter gives better insight on the already existing pre-treatment techniques and on the advances that are being developed and/or optimized in order to achieve closed-loop recycling. Some of these advanced pre-treatments include chemical washing to remove inks (deinking), extraction methods to remove undesired plastic additives and dissolution-based pre-treatments, such as delamination and dissolution-precipitation techniques.

Deinking of recycled office (MOW) paper was carried out by using a flotation column and adding separately sodium hydroxide, and the enzyme Cellulase Thricodema Sp., as defibrillators. The de-inked cellulose fibers were characterized according to the standards of the paper industry, to compare the efficiency of the deinking of each chemical reagent used to hydrolyze the fibers and defibrillate them. The computational simulation of the molecular coupling between the enzyme and cellulose was performed, to establish the enzyme-cellulose molecular complex and then to identify the principal amino-acids of endo-β-1,4-D-glucanase in this molecular link, which are responsible for the hydrolysis of the cellulose. Experimental results show the feasibility to replace sodium hydroxide with the enzyme Cellulase Thricodema Sp., by obtaining deinked cellulose with similar optical and physical properties. The use of the enzyme instead of sodium hydroxide avoids the contamination of the residual water; in addition to that, the column is operated more easily, taking into consideration that the pH of the system goes from alkaline to neutral.

The effects of cellulase enzymes (Trichoderma reesei) in flotation deinking of mixed office wastes (MOW) on the deinking efficiency, physical and optical properties of the papers were investigated....

Water-based flexographic-printed ink has attracted much attention due to the reduced emission of volatile organic compounds in the printing process. However, it is difficult to remove water-based ink particles with small particle size and high hydrophilicity because they are easily reabsorbed onto cellulosic fibers during wastepaper recycling. In this paper, the absorption mechanism of water-based ink particles onto fibers was studied by using isotherm models and adsorption dynamic kinetics models at different temperatures. The adsorption process was fitted to the Freundlich isotherm, and the adsorption behavior was spontaneous and exothermic processes with an increase of entropy. It fitted well with the pseudo-second-order rate model, and the equilibrium adsorption amounts at three temperature conditions were 2.55, 2.34, and 2.21 mg/g, respectively. The B value was 9.20 g·mg−1·min−1, and the Ea value was 15.6 kJ·mol−1. The results showed that it was easier to remove the water-based ink particles from cellulosic fibers under shorter contact time and higher operation temperature during wastepaper recycling. It would be helpful to optimize the wastepaper recycling operation and to develop a novel deinking process.

Alkaline organic residues, such as wood ash (WA), deinking paper sludge (DPS), and mixed paper sludge (MPS) could have a significant potential for mitigating greenhouse gases (GHG) when they are used for land application. The DPS was mixed and then granulated with MPS, WA and/or composted DPS to form pellets. A 56-d incubation study was carried out to investigate the effect of alkaline organic residue pellets on: (1) the biological and chemical properties of acidic clayey soil; (2) on carbon dioxide (CO2), on methane (CH4), and nitrous oxide (N2O) soil emissions. The experimental design included eight different treatments: unfertilized control (Control), fertilized control with mineral nitrogen (controlF), and six pelleted alkaline organic residue amendments (T1–T6) combined with mineral nitrogen fertilizer. The six amendments were: (T1) 100% DPS; (T2) 100% composted [50% poultry manure and 50% T1]; (T3) 50%WA + 50% T1; (T4) 50% WA + 50% T2; (T5) 50%T2 + 30%WA + 20% MPS; (T6) 50% T1 + 30%WA + 20% MPS. The results showed that alkaline residues significantly increased soil pH, the concentration of water-extractable organic carbon, and water-extractable nitrogen. Alkaline treatments had a positive effect on soil microbial activity. The highest mitigation efficiency of cumulative CO2 was obtained with T4, which released 10% less CO2 than other treatments. No significant effect on cumulative CH4 emissions was observed. Total cumulative N2O emissions were reduced by 37% with T5. Our study also showed that organic pellets based on alkaline residues improved the soil properties and can play a role in the mitigation of GHG in acidic clayey soil. Therefore, the co-application of alkaline organic residue pellets with chemical fertilizer might be considered as a sustainable approach in agriculture.

The use of enzymes in the bio-deinking process of newspaper waste has promising potential. However, investigations on the concentration of enzyme combinations need to be carried out to obtain the optimum ratio of cellulase and laccase enzymes for the bio-deinking process of recycled newspapers. The mixture of the two enzymes at various ratios was used to remove the ink on paper pulp from used newspapers by mechanical disintegration method treatment and followed by the bio-deinking process in an incubator shaker. The characterization of functional groups, structures, and thermal properties of bio-deinked pulp paper was carried out by FTIR, XRD, DTG/TGA, and an analysis of the degree of brightness to the prepared paper. FTIR results confirmed three main components of papers, such as cellulose, hemicellulose, and lignin. The XRD results showed that the equal ratio of cellulase and laccase enzymes had an effect on a higher crystallinity index, which was 78.8% compared to those obtained from the conventional methods with a crystallinity index of 69.7%. Thermal analysis showed that the optimum combination of both enzymes contributed the most at the highest temperature where the rate of degradation decreased. Brightness analysis showed that bio-deinking had met the quality requirements for newsprint paper in SNI 7273:2008. Our findings show that the combination of cellulase and laccase enzymes at the same ratio can produce optimal bio-deinked pulp for paper fabrication with excellent characteristics in brightness, thermal, and physical properties.

The efficiency of xylano-pectinolytic enzymes, co-produced by a single microbial strain Bacillus pumilus, was analysed for the recycling of mixed office waste paper through deinking and compared with the alkaline chemical deinking method. Enzymes showed maximum deinking at pH 8.5, pulp consistency of 10%, xylanase-pectinase dose of 12 and 4 IU per gram pulp, respectively, after 120 min of deinking period, and temperature at 50 °C. A chemi-enzymatic approach was employed with xylano-pectinolytic enzymes and various concentrations of deinking chemicals, which showed that enzyme-treated mixed office waste pulp requires only 40% chemicals for deinking, in order to get the almost same level of various handsheets properties, as obtained by the chemical method with 100% chemicals. Similarly, the effluent load of BOD and COD contents was also decreased by 17.90 and 19.75%. This combinational approach of deinking significantly improved the various properties of the handsheets and resulted in gain of 7.5, 9.38, 6.33 and 11.65% in tear factor, burst factor, breaking length and viscosity of the handsheets, while the effective residual ink concentration analysis of deinked handsheets of mixed office waste paper showed deinking efficiency of 22.45%, which revealed the removal of ink particles during enzymatic deinking steps.

The ozone reactive flotation for deinking recovered cellulosic fibers, recently developed at lab scale, showed interesting results in terms of fiber yield and effluent pollution reduction with clas...

Printed newspaper is one of the print-based media published daily in large quantities. The focus of this research is to remove the ink from used newsprint with alkaline treatment by using ultrasound sonochemistry method. Newsprint sheets collected were characterized by mechanical and morphology tests using FT-IR, XRD, tensile test and SEM. FT-IR spectra analysis shows the absorption of C=C functional groups as the main components of newspapers at 1427 and 1635 cm-1 wavelengths. The treatment with alkaline solution increased the mechanical strength properties of paper. SEM morphology analysis result shows that the surface of paper becomes more rough after ultrasound-alkaline treatment compared to paper without ultrasound treatment (conventional treatment). The crystallinity value decreased with alkaline treatment. The longer the ultrasound duration was, the lower the crystallinity degree became.

The study is a first investigation of the feasibility to preserve recycled fillers (e.g. calcium carbonate, kaolin) from deinking paper sludge for newspaper production using an alternative approach respect to the actual methods. Deinking paper sludge was incinerated at 575 °C. The thermal stability of the incinerated sludge (ash) was evaluated by infrared analysis. Subsequently, the resulting ash was bleached by sodium dithionite. The particle size of the ashes was analysed by laser diffraction. The effect of recycled fillers on recycled paper pulp, after blending, was evaluated by the analysis of the physical and optical properties of the obtained paper sheets. Analysis showed the conservation of the calcium carbonate and other fillers’ molecular structure, both after incineration of the sludge and after bleaching. The dithionite treatment of the ashes resulted in ISO brightness levels of more than 70. The brightness was stable over one month. Paper sheets made by blending the bleached ashes with recycled paper showed an improvement of brightness and opacity but a decrease in terms of porosity and breaking length compared to paper sheets made without any filler. The proposed method still requires further studies to evaluate the economical application but offers an opportunity for the recycling of inorganic materials and valorisation of the sludge.

Mixed office waste paper (MOWP) is a low cost, high quality and easily collected fiber source for the papermaking industry. Unfortunately, limits in the application of traditional deinking are related to the negative environmental impacts of using chemicals during the deinking process. Hence, enzymatic deinking has received growing attention in the last decade. This study investigates the effect of using the effective enzymes produced from Rhizopus microspores AH3 which is grown on watermelon peel waste (WPW) extract, as a bio-deinking method in the deinking of MOWP, which is difficult to recycle because of their ink type and printing process. The methodology involves preparation of samples, impregnation with water, enzymatic treatment, washing, papermaking, evaluation of the produced paper sheets. The evaluation includes determination of the optical and mechanical properties as well as topographic investigation via scanning electron microscope of produced paper sheets. The results showed that there is an improvement in both optical and mechanical properties of all paper sheets produced in this study. The best enhancement was for medium B30 which was extracted by boiling of WPW for 30 min. This treatment gave high enhancement because of the effect of the produced enzymes from Rhizopus microspores AH3, where cellulase, xylanase, lignin peroxidase, poly phenol oxidase and laccase were 1.62, 1.49, 1.38, 1.2 and 1.5 U/ml, respectively. Moreover, the tensile strain (maximum load) increased by about 77% as well as the brightness percentage achieved about 86.78% and the deinking ability was increased approximately 16%.

Bioethanol production using paper wastes seems a promising approach towards sustainable energy, but mainly hindered by hazardous ink. Therefore, in our experimental plan various methods were applied for the deinking of waste newspapers, laser printed papers and examination papers. A newly designed paper pulper reduced the pulping time from 6 h to 2 h. Cellulase (15 FPU/g) from Aspergillus oryzae MDU-4 was found effective for the deinking of newspapers, whereas laccase isozymes (150 U/g) from Ganoderma lucidum MDU-7 along with 2 mM HOBt was preferred for the ink removal and degradation from the examination papers. Ozonation in the presence of Tween-80 was found to be efficient in the removal of toxic toners used in laser printing papers. The biologically and physically deinked papers, studied with the help of SEM, TEM, FTIR, and XRD analysis revealed significant changes in the chemical and surface structure. Moreover, the saccharification of deinked papers with the help of an enzymatic consortium of Trichoderma citrinoviride MDU-1 resulted in 305 mg/g, 377 mg/g, and 409 mg/g release of sugars from the newspaper, examination paper, and laser printed paper, respectively. Finally, the enzymatic hydrolysates fermented with Saccharomyces cerevisiae NCIM-3640 produced 3.35 g/L ethanol, with 40.85% ethanol yield.

The biotechnological use of xylans and xylanases has grown remarkably. Xylanases have stimulated great interest due to their potential application in several industries. Over the years the number of possible applications of xylanases in the pulp and paper industry has increased steadily, and several applications have been commercialized. Xylanases are being used for prebleaching pulp, modifying fiber, deinking, dedarking, and producing dissolving grade pulp. Apart from its use in the pulp and paper industry, xylanases are also used as food additives to poultry; in wheat flour for improving dough handling and quality of baked products; for the extraction of coffee, plant oils, and starch; in the improvement of nutritional properties of agricultural silage and grain feed; in combination with pectinase and cellulase for clarification of fruit juices; and in the degumming of plant fiber sources such as flax, hemp, jute, and ramie. Use of xylanases could greatly improve the overall economics of processing lignocellulosic materials for the generation of liquid fuels and chemicals. Xylanase and cellulase, together with pectinases, account for 20% of the world enzyme market.

On the market there are increased quantities of laminated cardboard packaging with glossy surface. Laminated packaging is being used for its appealing appearance. However, laminated paper treatment creates additional problems in the process of recycling of used product. Adhesives and foil are a specific issue in the separation of impurities in recycled paper. It is crucial that the paper packaging products contained in the paper for recycling are repulpable within standard operating time and equipment. In this research three methods (without chemicals, INGEDE 11 and their combination) of removing impurities from paper pulp are compared and their efficiencies are determined to gain deeper insight into the recycling process. The procedures determine the recyclability of existing printed material, as well as the possible adhesive and material improvements. A specific issue in the separation of impurities was the presence of adhesives as well as silver foil (BOPET metallized film) for lamination. All three applied procedures successfully separate impurity particles from paper pulp and printed laminated boxes in a more sustainable manner, without the use of chemical agents.

Cellulose nanocrystals (CNC) were successfully prepared from waste newspapers through a simple pretreatment and hydrolysis process. The Fourier transform infrared spectroscopy (FTIR) result for the CNC suggested that no new chemical bonds were formed during the preparation of CNC. X-ray diffraction results indicated that the crystallinities of the deinked and untreated waste newspapers were 66% and 73.8%, respectively. Greater smoothness of the deinked waste newspapers fibers could be clearly observed by scanning electron microscope (SEM), which was attributed to the removal of ink from the chemical treatment. The transmission electron microscopy (TEM) and atomic force microscopy (AFM) results of the CNC revealed a needle-like natural fiber with a length of 300 nm to 600 nm, a diameter of 10 nm to 30 nm, and an aspect ratio in the 10 to 60 range. The obtained CNC particles were found to improve the physical properties of paper sheets, specifically that of the tear, tensile, and burst indices. The maximum increase in the physical properties was achieved with a 5.5% CNC addition.

The printing ink on the plastic surface will greatly reduce the quality of recycled plastic products. In this work, quaternary ammonium modified waste cooking oil (WCOQE) was fabricated using waste cooking oil, epichlorohydrin and trimethylamine aqueous solution as raw materials, through ring-opening esterification and quaternary amination reaction. The synthesis conditions of WCOQE were optimized, and the structure and properties of WCOQE were characterized by FTIR, zeta potential and 1H NMR. Furthermore, WCOQE had excellent emulsifying performance, low kraft point, low CMC value, good foaming and stability, which could effectively reduce the surface tension of water, showing application potential in the field of plastic deinking. Importantly, compared with the waste cooking oil without deinking effect, the WCOQE had an excellent deinking performance on the ink on plastic surface, and the deinking efficiency could be improved by increasing the concentration of deinking agent, the deinking temperature, and prolonging the pre-soaking and stirring time. The results of AFM, EDS, optical photos and Leica microscope showed that the roughness changed significantly, and the ink molecules were gradually peeling off. This work highlighted the potential of quaternary ammonium modified waste cooking oil for excellent removal of printing inks on plastic surface.

This study introduces a novel geotechnical composite material comprising two types of fill material sourced from the paper industry-deinking paper sludge ash (DPSA) and deinking paper sludge (DPS). Five composites with different DPSA and DPS contents were investigated. Two composites were selected for further analyses. The technology and procedure for composite installation were implemented in field tests. The composites with 80% and 70% DPSA exhibited the elasticity required to withstand minor landslide slip deformations, in addition to achieving sufficiently high values of uniaxial compressive strength. The composites had a low maximum dry density value, which led to fewer settlements in the entire support structure. The enhanced shear characteristics can enable the construction of a thinner retaining wall. The delay between preparation and installation of the composites was further investigated. The field tests confirmed that the composites with 80% and 70% DPSA can be installed on the construction site 4 h and even 24 h after mixing. In 2018, a retaining wall structure with 70% DPSA and 30% DPS was successfully implemented near a railway line using conventional technology as followed-up research to the herein presented study. Results have been derived from work performed in the scope of the H2020 Paperchain project in which novel circular economy models centered on the valorization of the waste streams generated by the pulp and paper industry as secondary raw material for several resource-intensive sectors, including the construction sector, have been developed. Environmental benefits are savings in natural raw materials, reduction of landfill disposal as well as CO2 emission reduction. Nasl. z nasl. zaslona. Opis vira z dne 16. 11. 2021. Št. članka 22363. Bibliografija: str. 12-13. Abstract.

Deinking of Mixed Office Waste [MOW] paper was carried out by using a flotation device and adding enzymes as defibrillators. Employing the computational simulation of the molecular coupling between the cellulase enzyme obtained from Trichoderma sp. and cellulose, the enzyme-cellulose molecular complex and the main amino acids endo-β-1,4-D-glucanase of this molecule, responsible for the hydrolysis of cellulose, were obtained. Three of these amino acids were used for deinking. The deinked cellulose fibers were evaluated according to the standards of the paper industry (ISO whiteness [brightness], factor of reflectance, opacity, and tonality) to determine the efficiency of deinking. The experimental results show that the best optical characteristics of the sheets of deinked paper with amino acids are those where a mixture of aspartate, glutamate, and asparagine was applied, instead of their individual dosage. In addition to the aforesaid, the use of enzymes instead of the traditionally used reagent, such as sodium hydroxide, avoids the contamination of wastewater; additionally, the operation of the column is carried out easily, taking into consideration that the pH of the system goes from alkaline to neutral.