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A pre-treatment process was evaluated in this work for wastewater from paper recycling using microwave technology followed by rapid precipitation of contaminants through centrifugation. Artificial neural networks (ANNs) were used to analyze and optimize the turbidity values. Thirty experimental runs were utilized including microwave (MW) power, duration, centrifuge time, and centrifuge speed as input variables, generated by the Central Composite Full Design (CCFD) approach. The experimental turbidity ranged from 8.1 to 19.7 NTU, while predicted values ranged from 8.4 to 19.7 NTU by ANN. The ANN model showed a robust prediction performance with low mean squared error values during training and testing. Moreover, high R2 values showed a remarkable agreement between the experimental observations and ANN predictions. The results obtained from the input values (A:150.00, B:60.00, C:15.00, D:30.00) of sample 2, which gave the lowest turbidity value, showed the most removal of pollution. The results obtained from the input values (A:250.00, B:60.00, C:7.00, D:20.00) of sample 30, which gave the highest turbidity value, showed the least removal of pollution. The results showed that increasing RPM and time of the centrifugation process significantly affected the removal of pollution in wastewater.

A pre-treatment process was evaluated in this work for wastewater from paper recycling using microwave technology followed by rapid precipitation of contaminants through centrifugation. Artificial neural networks (ANNs) were used to analyze and optimize the turbidity values. Thirty experimental runs were utilized including microwave (MW) power, duration, centrifuge time, and centrifuge speed as input variables, generated by the Central Composite Full Design (CCFD) approach. The experimental turbidity ranged from 8.1 to 19.7 NTU, while predicted values ranged from 8.4 to 19.7 NTU by ANN. The ANN model showed a robust prediction performance with low mean squared error values during training and testing. Moreover, high R2 values showed a remarkable agreement between the experimental observations and ANN predictions. The results obtained from the input values (A:150.00, B:60.00, C:15.00, D:30.00) of sample 2, which gave the lowest turbidity value, showed the most removal of pollution. The results obtained from the input values (A:250.00, B:60.00, C:7.00, D:20.00) of sample 30, which gave the highest turbidity value, showed the least removal of pollution. The results showed that increasing RPM and time of the centrifugation process significantly affected the removal of pollution in wastewater.

The production process of recycled paper generates a significant amount of wastewater. In many cases, the companies do not have a fully adequate effluent treatment system, due to the high cost of conventional physical or chemical treatment systems, which leads to contaminated wastewater. Due to this problem, this research aims to evaluate a bioremediation system based on a flotation system with Typha domingensis plants, for the recovery of wastewater generated in the paper recycling process. The effluent treatment system was installed in the vegetation house of the Multidisciplinary Center for Technological Research (CEMIT), San Lorenzo, Paraguay. It consisted of Typhas plants arranged in plastic containers, which were classified in relation to the effluent concentration (100 %; 50 %; 30 %), in three replicates. For the evaluation of efficiency, physicochemical determinations of pH, temperature, turbidity, conductivity, BOD5, COD, total phosphorus and total nitrogen were carried out at 7-day intervals over a 4-week period. The results obtained indicate significant differences in the percentage of removal of the different pollutant concentrations, where the COD and BOD5 parameters showed removal values of 99 % and 92 %. In the case of Total Nitrogen and Total Phosphorus the values were around 92 % and 75 %, respectively, demonstrating the efficiency of the plant in the treatment of the effluent. This kind of wastewater treatment system has the potential to decrease the load of effluent pollutants produced in paper recycling. Therefore, this study concluded that the system composed of T. domingensis is an option as a potential phytoremediation system for the treatment of wastewater from paper recycling.

Due to the high wastepaper recyclability and water-loop system closure, packaging paper mills struggle with increased fines, causing runnability issues. Cellulase enzymes are a preferred treatment choice for the improvement of the pulp refining in stock preparation area but are not widely used or easy to introduce in the production process. Different cellulase enzymes were tested, and those with the highest activity were introduced to the white-water (WW) samples with the aim to reduce fines content as potentially new enzyme applications on the paper machine. The first portion of the study involved the development of an experiment model to find and confirm the optimal enzyme process parameters (40 °C, pH 5.7, reaction time 3 h, and 0.18% v/v enzyme addition) for laboratory made white-water. The second portion of the study included turbidity, colloidal charge, flow cytometry (FCM), and chemical oxygen demand (COD) analysis on industrial and laboratory made white-water samples at optimized process parameters. Obtained results corresponded to reduced fines content in white-water samples, which justified commercial usage of cellulase enzymes on recycled paper machine short loop and potentially increased machine runnability without negative influence on wastewater treatment plant.

Due to the high wastepaper recyclability and water-loop system closure, packaging paper mills struggle with increased fines, causing runnability issues. Cellulase enzymes are a preferred treatment choice for the improvement of the pulp refining in stock preparation area but are not widely used or easy to introduce in the production process. Different cellulase enzymes were tested, and those with the highest activity were introduced to the white-water (WW) samples with the aim to reduce fines content as potentially new enzyme applications on the paper machine. The first portion of the study involved the development of an experiment model to find and confirm the optimal enzyme process parameters (40 °C, pH 5.7, reaction time 3 h, and 0.18% v/v enzyme addition) for laboratory made white-water. The second portion of the study included turbidity, colloidal charge, flow cytometry (FCM), and chemical oxygen demand (COD) analysis on industrial and laboratory made white-water samples at optimized process parameters. Obtained results corresponded to reduced fines content in white-water samples, which justified commercial usage of cellulase enzymes on recycled paper machine short loop and potentially increased machine runnability without negative influence on wastewater treatment plant.

The objective of this work is to produce an ecologically friendly material for use in Ivory Coast's construction sector in the future. These materials should have good thermal qualities and be flame resistant in addition to helping to achieve interior comfort. The fundamental components under consideration are freely accessible in Ivory Coast and include clay mortar as a fire retardant, potato starch as a binder, and recycled paper granules as a filler. The suggested ecologically friendly material's manufacturing process is fully described in detail. After conditioning, the team created multiple samples, taking into account that each test that the materials are put through requires various probe sizes for the thermal conductivity test, the reaction to fire test, and the flexural strength test. The best result regarding thermal conductivity of composites was obtained when 10 % clay is added in the mixture, namely between 0.057 … 0.068 W/(mK). During the ignitability tests the flame did not propagate to a height greater than 15 cm throughout the 60 s test time, so it can be concluded that the materials match minimally in the class E of reaction to fire. The flexural strength of tested materials was under 0.8 MPa.

Chemical surface modification is one method for enhancing the mechanical and barrier properties of packaging paper. The NaOH/urea solvent system has been deemed an effective, inexpensive, and cost-effective solvent for paper modification and cellulose dissolution due to its unique self-reinforcing qualities and the fact that it can be utilized on an industrial scale, although it is ineffective for porous paper and requires pre- or post-treatment. This study examined the influence of acid as a post-treatment on the surface modification of paper with NaOH/urea to improve properties relative to packaging uses. The results indicated that NaOH/urea modification on OCC as a semi-crystalline material did not result in materials with superior resistance and barrier qualities. While acid treatment increased tensile and burst strength and air permeability, it was ineffective at increasing tear strength. Properties of control, NaOH/urea treatment, and acidic post treatment papers were respectively 33.31, 29.4, and 37.46 mn/g in the tensile index, 1.7, 1.58, and 1.74 Kpa.m2/g in burst index, 9.94, 9.07 and 8.87 mn.m2/g in tear index, 2.04, 1.34 and 1.32 s-1 in smoothness, 37.2, 38.2 and 45.4 s in air resistance, and 77.5, 90.8 and 80.5 water absorption. Therefore, with or without acidic post-treatment, the sheets became hydrophilic.

Chemical surface modification is one method for enhancing the mechanical and barrier properties of packaging paper. The NaOH/urea solvent system has been deemed an effective, inexpensive, and cost-effective solvent for paper modification and cellulose dissolution due to its unique self-reinforcing qualities and the fact that it can be utilized on an industrial scale, although it is ineffective for porous paper and requires pre- or post-treatment. This study examined the influence of acid as a post-treatment on the surface modification of paper with NaOH/urea to improve properties relative to packaging uses. The results indicated that NaOH/urea modification on OCC as a semi-crystalline material did not result in materials with superior resistance and barrier qualities. While acid treatment increased tensile and burst strength and air permeability, it was ineffective at increasing tear strength. Properties of control, NaOH/urea treatment, and acidic post treatment papers were respectively 33.31, 29.4, and 37.46 mn/g in the tensile index, 1.7, 1.58, and 1.74 Kpa.m2/g in burst index, 9.94, 9.07 and 8.87 mn.m2/g in tear index, 2.04, 1.34 and 1.32 s-1 in smoothness, 37.2, 38.2 and 45.4 s in air resistance, and 77.5, 90.8 and 80.5 water absorption. Therefore, with or without acidic post-treatment, the sheets became hydrophilic.

ABSTRACTThe effect of bamboo virgin pulp addition to the recycled pulp in enhancing the recycled paper’s mechanical properties was evaluated. Malaysian bamboo virgin pulp used in this research were Bambusa vulgaris (Aur bamboo), Gigantochloa levis (Beting bamboo), and Gigantochloa scortechinii (Semantan bamboo). The addition of 2.5, 5, 7.5, and 10 wt% of bamboo virgin pulp improved the burst index, folding endurance, tearing index, and tensile index of the recycled paper from 2.27 to 3.17 kPa.m2/g, 7 to 15 double folds, 5.98 to 8.27 mN.m2/g, and 24.86 to 32.40 Nm/g, respectively. These were equivalent to the increment percentage for burst index, folding endurance, tearing index, and tensile index at the range of 6.61 to 39.65%, 28.57 to 114.29%, 15.72 to 38.59%, and 10.50 to 33.87%, respectively. The application of bamboo virgin pulp is very promising in improving the recycled paper’s mechanical properties and this could be further extended in enhancing the other properties such as physical and optical paper properties.

Recycled fibers used in the manufacturing of paper and board are associated with strength deficiencies. This study investigated the use of TEMPO-oxidized nanocellulose from oil palm empty fruit bunch (OPEFB-TEMPO) for reinforcing papers made from such fibers. Strength properties of tensile and tear were enhanced with the addition of OPEFB-TEMPO, with strong correlations, as indicated by the R2 values. The reinforcement capability was supported by the scattering coefficient-percent relationship. The only drawback of the nanocellulose addition is that it reduces pulp drainability, which can be minimized by adding drainage aids. Because only a relatively small amount is required, OPEFB-TEMPO has the potential to be used as paper strengthening agent, particularly in the production of low grammage papers.

Recycled fibers used in the manufacturing of paper and board are associated with strength deficiencies. This study investigated the use of TEMPO-oxidized nanocellulose from oil palm empty fruit bunch (OPEFB-TEMPO) for reinforcing papers made from such fibers. Strength properties of tensile and tear were enhanced with the addition of OPEFB-TEMPO, with strong correlations, as indicated by the R2 values. The reinforcement capability was supported by the scattering coefficient-percent relationship. The only drawback of the nanocellulose addition is that it reduces pulp drainability, which can be minimized by adding drainage aids. Because only a relatively small amount is required, OPEFB-TEMPO has the potential to be used as paper strengthening agent, particularly in the production of low grammage papers.

This study aims to review the relation between papercrete and recipanel (wall materials from recycled paper) with indicators of material sustainability in environmental aspects. Recycling paper into wall material is one of the ways to overcome the increasing amount of paper waste in Indonesia. Waste recycling is related to the concept of sustainability, namely the triple bottom line of the concept of sustainability. A literature review of waste management, recycled paper, and recycled paper as wall material were conducted in terms of environmental sustainability. This study was conducted by integrating the theoretical understanding of waste, walls, wall material products from recycled paper and discussion of its impact in terms of the sustainability of recycled paper as alternative wall material. From this study, it was found that the relationship between the characteristics of papercrete and walls on the sustainability of recycled paper brought forward four positive values and two negative values. Meanwhile, the relation between recipanel and wall characteristics on the sustainability of recycled paper carries four positive values and two negative values. Thus, the recycled paper used as wall material with examples of papercrete and recipanel products may still be suitable for use as wall material in Indonesia. Suggestions resulted from this study that might be implemented in the future are to increase the durability of materials derived from recycled paper and to conduct studies that discuss wall materials derived from recycled paper from social and economic aspects in terms of sustainability.

Nowadays, the attention in many industries is shifting towards the problem of waste overproduction and production of the waste in general. This study aimed to find an alternative approach to the production of packaging which will be environmentally friendly and at the same time optimal in terms of the print quality. This was accomplished by using the minimal needed amount of material for the production of packaging and adjusting the parameters of the flexographic printing process to achieve the desired visual impression of the print. The designed motive for the packaging was printed on five different recycled papers, following the guidelines of sustainable design. Printing was performed on each recycled paper with different printing pressures (50N, 150N, and 400N). Smoothness was measured on each paper; and for every printed sample, colorimetric measurements and thickness of the lines in positive and negative were measured. Print contrast for each print was calculated, and microscopy of fine printed elements was performed. All chosen papers except one had average smoothnes of up to 3.2 s (the smoothest paper had the average smootheness value of 54.72 s). Smoothness results influenced the printed line widths. Specifically, when increasing the printing pressure, a significant deformation of the line width has occured on all papers except the smoothest one (deformations of the lines printed in positive were up to 400 μm for rough papers compared to maximum of 60 μm for lines printed on the smoother paper). Similar results were obtained for the lines printed in negative. Furthermore, legibility of the printed typographic elements of 4pt size was significantly influenced by the smoothness of the paper. Elements printed on the smoothest paper have displayed the negligible deformations when changing the printing pressure. For other papers, elements in positive were optimally printed by 50 N pressure, and elements in negative by the pressure of 400 N. The results of this research have enabled the optimization of the flexographic printing process when using each of the five types of recycled papers. Furthermore, the presented qualitative and colorimetric parameters of the prints enabled the assessment of the applicability of used papers as printing substrates for ecologically favorable packaging.

Converting biomass into jet fuel involves more than the core chemical process. The overall process includes the logistics of harvesting and transporting the biomass, handling and preparing the material for processing, and processing and disposal of waste. All of these activities contribute to cost. Controlling cost involves more than developing efficient process chemistry. Choice of feedstock also has a significant impact on process economics. We consider chemical conversion of paper from municipal solid waste as a feedstock for the production of jet fuel and diesel. Paper has a significantly higher cellulose content than raw lignocellulosic biomass such as corn stover, so it requires less pretreatment to convert it into hydrocarbons than lignocellulosic biomass. Our techno-economic analysis showed that the cost of converting paper waste into jet fuel is about $1.00/gal less than jet fuel produced from corn stover. Although the cost of recycling paper into jet fuel is less than producing it from corn stover, the process is not competitive with petroleum. We estimated a minimum selling price of $3.97/gal for paper-derived jet fuel. Our sensitivity studies indicated that the biggest economic obstacle is the cost of cellulose hydrolysis. Direct hydrogenation of paper to sugar alcohols combined with increased economy of scale could make recycling paper jet fuel competitive.

The use of mulch contributes to the reduction of water consumption and weed infestation in strawberry cultivation. Recycled paper, being biodegradable, has great potential to replace plastics. Thus, the objective was to evaluate the water consumption and agronomic performance of strawberry subjected to different wetted areas and mulches. The wet areas tested were 40% (WA40) and 70% (WA70) imposed by a drip irrigation system. The different types of mulch were: white polyethylene (WHP), black polyethylene (BLP), recycled paper (REP) and no mulch (NM). BLP, REP and WHP mulches promoted the same weed control. The number of fruits per plant, fruit length, fruit yield, and water productivity did not differ for the factors wetted area and types of mulch. Higher fruit mass and diameter were found in the WA40 treatment, while the mulches favored only fruit mass. Thus, fruit yield showed no difference, and only water consumption differed between the wet areas and between the types of mulch. Strawberry water consumption was higher in WA70. In relation to fruit waste, it was found that the WHP and BLP mulches provided higher values than REP and NM. Thus, the recycled paper, combined with a wet area of 40%, is recommended as a mulch in strawberry production.

The change in the dimension (Thickness Swelling; TS) was found to be high, at high boric acid content for boards made from Office paper/Newspaper (O/N) and Office paper/Old Corrugated Container (O/C) types. However, the boards made with 10% boric acid exhibits higher Modulus of Rupture (MOR) values than boards made with 5.0% boric acid. The highest value of MOR was found as 7.93 MPa with the addition of 10% boric acid with Newspaper/Old Corrugated Containers (3:1 by weight) mixtures. The Modulus of Elasticity (MOE) of the boards generally decreased with increasing boric acid content from 5% to 10% in furnishes. The Office paper/Newspaper had the highest MOE among the all formulations and considerable higher than standard value of 600 MPa. However, the highest value of MOE was found as 735.63 MPa with the mixture of 3:1 (by weight) proportions of Office paper/Newspaper proportions. The similar results were observed for Internal Bond (IB) properties of boards, as like MOE. While in general, increasing boric acid content from 5.0 to 10%, negative effects on IB properties of boards. It was also realized that the boric acid content and fiber proportions effects various level on thermal properties (thermal conductivity; TC). The boric acid had usually provided higher thermal resistance, but the difference between fiber proportions and fiber types consisting of boric acid was important. However, the lowest TC value of 0.1455 W/mK was found the boards made from only old corrugated containers fibers with 10% BA content. The sound absorption values of boards made from secondary fibers show a sound damping that it was steady increase up to 1600 Hz and then decreasing. It could be realized that the sound absorption properties of boards were generally better than that of in lower frequencies.It was also realized that the boric acid content and fiber proportions effects various level on thermal properties (thermal conductivity; TC). The boric acid had usually provided higher thermal resistance, but the difference between fiber proportions and fiber types consisting of boric acid was important. However, the lowest TC value of 0.1455 W/mK was found the boards made from only old corrugated containers fibers with 10% BA content. The sound absorption values of boards made from secondary fibers show a sound damping that it was steady increase up to 1600 Hz and then decreasing. It could be realized that the sound absorption properties of boards were generally better than that of in lower frequencies.

The objective of this research is to design an approach for selecting appropriate solutions to efficiently and productively reduce environmental pollution and water, energy and raw material consumption in a recycled paper manufacturing facility, the paper mill in Latif, Iran. To reach this goal, we develop a decision-making model using the Analytic Hierarchy Process (AHP). The proposed model provides a framework for cleaner production implementation specific to the paper industry. Pairwise comparisons of the results of designed questionnaires resulted in the hierarchy model being divided into five major groups: production modification; process change; preventive maintenance; renewal; and manpower resources.These five groups include 31 sub-criteria and seven alternatives. The results showed that process change yields the highest priority among the main criteria and that industrial automation and its technology level gives the highest priority among sub-criteria. Regarding the alternatives, reduction of environmental pollution is the most important solution for cleaner production in the industry. Also, product modification is the most sensitive criterion affecting the alternatives priority.

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%.

Cationic rosin has many uses in papermaking; however, its performance as an internal sizing agent differs depending on the circumstance, especially in the recycling of pulps. In this study, a comprehensive laboratory approach was used to investigate the process variables affecting the cationic rosin application in the paper recycling process. In this respect, four levels of alum (0.5, 1.0, 1.5, and 2.0%) and four levels of cationic rosin (0.5, 1.0, 1.5, and 2.0%) were considered to find the best alum/cationic rosin combination in acidic conditions (pH 5). After considering all aspects of the paper, such as the mechanical properties (tensile, burst, and tear indices), wet resistance (Cobb test and dynamic contact angle test), and chemical usage (economically and environmentally-friendly procedures), the 1.0% alum and 0.5% cationic rosin levels were selected for optimum performance. This research also showed that the combined effect of alum with cationic rosin was favorable. Moreover, the sequence of alum and cationic rosin addition, which is a challenge in paper mills, also should be considered. The results indicated that the addition of cationic rosin after alum obtained the best mechanical and wet resistance results. In addition, the results showed that both acidic and neutral pH were acceptable in this sizing process.

Corn stalk, an agricultural waste, was valorized by the production of cellulose nanofibers (CNF), which were tested for improving recycled paper properties. CNF from eucalyptus kraft pulp (E-CNF) was used as a reference. Addition of 0.5% wt. CNF produced from corn organosolv pulp (C-CNF) to recycled paper increased the tensile index by 20%, whereas the same improvement with E-CNF was achieved at 1.5% wt. Tensile index was further enhanced by increasing the E-CNF, whereas C-CNF achieved its maximum effect at this dose. Different recycled furnish compositions were studied to evaluate C-CNF as a product additive. C-CNF improved tensile strength in all the different recycled furnishes studied. The tensile index improvement caused by C-CNF did not depend on the proportions of old newspaper and old magazine paper used. Addition of C-CNF to recycled corrugated board fluting increased the tensile strength, but to a slightly lower extent than in the case of recycled newsprint paper.

Recycled paper is commonly used in food packaging industry, especially for disposable products. The material coming into direct contact with food products must not represent a source of contamination for food in accordance with the Framework Regulation (EC) No. 1935/2004 containing the general requirements on all food contact materials. In the present study, the microbial purity of 31 paper-based materials with different contents of recycled matter (0-100%) was evaluated using a standard method based on the disintegration of paper. The results of the present study indicate the existing relation between the use of recycled fibers and the content of microorganisms. The increased amount of recycled fibers significantly increased the amount of bacteria in the paper samples. The highest content of microorganisms was observed in the case of paper with the highest recycled fiber content. Total counts of bacteria ranged from 5.0 × 101 to 1.2 × 105 CFU/g. Moulds were detected only in three paper samples. As the microorganisms present in food packaging may penetrate into foodstuffs (particularly those with high contents of water or fat) and have an adverse effect on end-consumers' health, microbial criteria for food packaging should be included into the EU legislation.

Rice straw cellulosic ethanol fermentation waste (CEFW) and municipal solid waste derived fiber (MSWF) were used as alternative fibers for recycled paper making. The fibers were mixed with old newspaper (ONP) fiber at different mass ratios to produce standard recycled papers and paperboards. A “green” adhesive binder derived from kraft black liquor (BLDB) was used to improve the physical properties of the waste-derived paper products. The values of these properties increased linearly with increasing average fiber lengths, regardless of the type of fiber used in the products. BLDB improved the physical properties of the products by 50% for papers and 85% for paperboards, and the performance of this binder was comparable to a commercial urea formaldehyde resin binder. Thermal pressing, however, did not improve the physical properties of the binder-enhanced paper products. With the addition of the adhesive binder, CEFW and MSWF showed reasonable substitution potential for ONP fiber by providing suitable tensile and bursting strength in the recycled paper products. The critical fiber length, which produced the minimum strength properties for the recycled paper products, was approximately 1020 m.

Recycling and deinking processes cause fiber damage because of hornification phenomena and increased external fibrillation. Mechanical refining has been used for many years to enhance the mechanical properties of paper. Biorefining of pulp using enzymes is receiving increasing interest for energy reduction at the refining step of the paper-making process. Moreover, enzymes have also been used for the enhancement of mechanical properties without affecting the drainage rate. As an alternative to mechanical refining treatment, a combination of an enzymatic treatment and cellulose nanofibril (CNF) addition was explored to enhance the mechanical properties of paper. The tests were carried out on a deinked pulp (DIP) suspension made of 50% old newspapers (ONP) and 50% old magazines (OMG). Various enzyme charges and CNF amounts were added to the mixture of ONP and OMG. All pulps (treated and untreated) were characterized from a morphological point of view, and the paper sheets made thereof were mechanically characterized. The combination of the enzymatic treatment with the addition of 3% CNF provided sufficient tensile strength for the paper to be used in high-performance applications.

Cabbage (Brassica oleracea) seeds were germinated and grown for 35 days in an organic standard substrate contained in either plastic, peat, paper, or newspaper containers to determine whether the container material might affect growth. Days to emergence, days to first leaf, and developmental morphological traits and physiological characteristics were monitored. Differences in evaporation and pH of water in contact with the containers were measured in separate experiments. Evaporation was lowest from plastic and highest from peat containers, while pH was lowest with water in contact with peat containers. Plant growth was fastest and most robust in plastic containers as demonstrated by their shoot height, stem diameter, and root and shoot dry weights. Seedlings grown in newspaper containers presented exceedingly poor growth and showed signs of stress.

Current product composition and quality test methods for the paper and pulp industries are rooted in wet-bench chemistry techniques which cannot be used to distinguish between virgin and secondary fibers. We have recently demonstrated the application of an in situ and nondestructive assessment method based on dielectric spectroscopy (DS), which can address this deficiency in the testing of paper. The DS technique, which employs a resonant microwave cavity, could be applicable to quality assurance techniques such as gauge capability studies and real-time statistical process control (SPC), and may have inherent forensic capabilities. In this paper, we show how this DS technique can be used to distinguish between office copier paper products which may contain recycled fibers. We show a reasonable correlation between the dielectric characteristics (e.g., dielectric loss) and the atomistic level chemical changes that result from the paper recycling process.

Newspapers have a limited lifespan, and therefore represent a focus of used and disposed paper. While these refuses have a considerable value and can be easily recycled, a considerable fraction ends in landfill. The authors show the possibility of adding value to used newspaper and enlarge its value chain. Old newspaper incorporates a high amount of wood fibers able to be used as reinforcement. On the other hand, this material also incorporates inks and other components inherent to newspaper production. In this work, the authors disintegrate old newspaper to recover and individualize wood fibers. A morphological analysis showed that the recovered fibers had aspect ratios higher than 10, revealing, a priori, their strengthening capabilities. Thereupon, these fibers were compounded with polypropylene at different contents, ranging from 20% to 50% w/w. It is well known that wood fibers are hydrophilic, while polyolefin are hydrophobic. This is a drawback to obtaining strong interfaces. Thus, two sets of composites were produced, with and without a coupling agent. The results showed that uncoupled composites increased the flexural strength of the matrix but reached an equilibrium point from which adding more reinforcement did not changer the flexural strength. On the other hand, the coupled composites showed a linear increase of the flexural strength against the reinforcement content. The flexural moduli of the coupled and uncoupled composites were very similar and evolved linearly with the reinforcement content.

The recycled paper and board industry needs to improve the quality of their products to meet customer demands. The refining process and strength additives are commonly used to increase mechanical properties. Interfiber bonding can also be improved using cellulose nanofibers (CNF). A circular economy approach in the industrial implementation of CNF can be addressed through the in situ production of CNF using side cellulose streams of the process as raw material, avoiding transportation costs and reducing industrial wastes. Furthermore, CNF fit for use can be produced for specific industrial applications.This study evaluates the feasibility of using two types of recycled fibers, simulating the broke streams of two paper machines producing newsprint and liner for cartonboard, to produce in situ CNF for direct application on the original pulps, old newsprint (ONP), and old corrugated container (OCC), and to reinforce the final products. The CNF were obtained by 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-mediated oxidation and homogenization at 600 bar. Handsheets were prepared with disintegrated recycled pulp and different amounts of CNF using a conventional three-component retention system. Results show that 3 wt.% of CNF produced with 10 mmol of NaClO per gram of dry pulp improve tensile index of ONP ~30%. For OCC, the same treatment and CNF dose increase tensile index above 60%. In both cases, CNF cause a deterioration of drainage, but this effect is effectively counteracted by optimising the retention system.

Paper dust is a kind of cellulosic waste that is generated by converting operations in paper mills. It was derived to a low-grade cellulose acetate in this study. Papers made from recycled fiber were then impregnated with the resultant cellulose acetate. Effects of impregnation conditions on the paper properties were statistically investigated by employing central composite design (CCD) based response surface methodology (RSM). Four response variables, namely density, burst index, smoothness, and rate of surface wettability were analyzed. Polynomial estimation model of each response was developed as functions of three independent variables, which are pressing temperature (T), dipping time (D), and concentration of cellulose acetate (C). The paper which was impregnated based on the calculated optimum condition (T: 163 oC, D: 2.8 minutes, and C: 2.7 percent), possessed a density of 0.5450 g/cm3, rate of surface wettability of 0.012o/s, burst index of 2.84 kPa m2/g, and paper smoothness of 475 mL/min. There was no significant difference between the experimental values and the predicted values calculated from estimation models. The cellulose acetate impregnated Braille papers made from recycled fibre was found to have better properties than those of commercial Braille paper in terms of rate of surface wettability and burst index.

This research work is based on the application of sampling techniques to optimize industrial processes. The paper industry purchases large quantities of recycled paper, which must undergo a quality control based on the determination of two variables: the weig ht and moisture content of the raw material. The latter is a decisive factor in paying to ea ch supplier,for this work is to establish a procedure to determine an optima/ estimator of the moisture content of recycled paper that comes in a transport medium to the yards of consumption of a paper industry, so that you can assign a value to pay that does not harm either the company or the supplier. In research, it was on a set of historical data and quality standards, and developing a process based on the sample analysis to obtain an estimate of the moisture associated with all the paper contained in that conveyance. Significantly, the results of this procedure, yield percentages of 98.32% acceptance with respect to the actual value, compared with 63.48% of the traditionally applied method.

Results are presented regarding the development of recycled paper based impedance biosensors with screen printed interdigitated electrode structures (IDES). The sensors show a response to increasing salt concentrations in the range 30–100 mM NaCl. To prove the feasibility of using recycled paper, biofunctionalization with a glucose sensitive enzyme mixture was performed by inkjet printing. The quantification of the glucose sensitive colour change reaction in paper was investigated and a trend is found in the range of 6–90 mg/dL. Subsequently, measurements with a wireless electronic readout system were performed on an electrochemical assay showing a decrease of the normalized sensor response dependent from the glucose concentration in the range 0–80 mg/dL.