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Bio-based additives received significant attention in pulp and paper properties improvement. For this, the most cited biochemical Cellulose Nano Fibrils (CNFs) and Cationic Starch (CS) were experimentally compared with the most declared synthetic chemical, Cationic Polyacrylamide (CPAM). SEM images showed better paper surface filling by the utilization of the chemicals. The three studied polymers, in solely or combination mechanism, improved mainly bagasse pulp and paper properties compared to the blank sample, except for pulp drainage, which decreased by CNFs to lower volumes presumably due to its intrinsic characteristics. Cationic polymers (CP) compared to CP/CNFs approaches increased pulp retention and drainage but decreased paper density and strengths. The best pulp retention and drainage achieved by CS followed by CPAM, while paper air persistency, density, and strength properties evaluated highest by CP/CNFs followed by CNFs. Generally, CS revealed a more significant improvement in pulp and paper properties than CPAM either with or without CNFs.

This study optimizes a novel surfactant-assisted green liquor dregs (GLD) pretreatment of paper mill sludge (PMS), both of which are wastes from the kraft pulping industry, using a combined Response Surface Methodology (RSM) design. Optimized conditions give a maximal reducing sugar release of 16.38 g/L. A substantial reduction in heavy metals aluminum, chromium, cobalt, arsenic, lead, and copper after pretreatment illustrates the enhancement of substrate digestibility by reducing toxic elements. Separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) for hydrogen production are assessed. SSF produced a hydrogen yield of 3.72 mL/g, displaying a 36.26% increase from pretreated PMS compared to SHF. These findings provide insights into possible methods of reducing process duration, energy input, and costs incurred with waste disposal within the paper industry. Furthermore, improved hydrogen yield using an SSF process demonstrates the potential beneficiation of pulp and paper GLD and PMS wastes.

Cellulose triacetate (CTA) forward osmosis (FO) membrane from Hydration Technology Innovation (HTI), USA was tested in a locally fabricated FO system to concentrate synthetic and pulp and paper mill wastewater. The industry is among the 17 most polluted industries with intensive water consumption and wastewater generation (MoEFCC, Government of India). The CTA membrane was studied with deionized water as feed solution and 1 M NaCl as draw solution, which resulted into water flux of 5.8 L/m2h and reverse salt flux of 0.2 g/L. A concentration stepping method was used to determine the critical draw concentration with lignin solution as the model feed. There was no deviation in flux between the baseline (deionized water feed) and the lignin solution up to 1.5 M NaCl, but a marginal deviation (8% and 21% respectively at 2 M and 3 M) was seen thereafter. The average water flux after 24 h FO study with synthetic wastewater as feed solution (draw solution 2 M NaCl) was 8 L/m2h, and 80% water recovery. Similar study with pulp and paper wastewater as feed solution (draw solution of 1.5 M NaCl) was 5.4 L/m2h was with 62% water recovery. Lignin and COD rejection in pulp and paper mill wastewater was 90% and 64% respectively. The preliminary results indicate that FO is promising for water and lignin recovery from waste streams.

Paper and pulp mills generate substantial quantities of cellulose-rich sludge materials that are disposed in landfills at a large scale. For sustainability purposes, sludge materials can be bioprocessed to produce renewable fuels and useful chemicals. The enzymatic hydrolysis of cellulose is the process bottleneck that affects the conversion economics directly by using zero-cost raw materials. In order to study and optimize the process, the characteristics of the sludge raw materials should be first evaluated. In this work, sludge samples were obtained from paper mills located at different locations in Wisconsin and Minnesota. Part of the sludge samples was washed (de-ashed) with hydrochloric acid while the other part remained unwashed. The samples were subjected to multiple spectroscopic analyses techniques to evaluate the morphological properties of cellulose fibers and to estimate the total structural carbohydrate content. The results showed that the de-ashing process changed some fiber characteristics and cellulose crystallinity structure in all sludge samples. Sludge sample A (obtained from Kraft pulp and recycled paper mill region) showed a high percentage of fiber, with crystalline cellulose, compared to the other two sludge samples suggesting that sludge A is a valuable source to make value-added products. Aspen Plus mass and energy calculations performed in view of the ‘zero’ cost and the reliable supply of sludge raw materials producing 2 mol H2/mol glucose. Moreover, the results showed that extracting crystalline cellulose from these sludge samples is more profitable than crystalline cellulose made from the other lignocellulosic feedstocks. The results reported here showed that the utilization of these sludge materials would be an economically attractive and promising alternative for the production of hydrogen.

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.

Recently, the interest in active packaging utilization has increased with population growth, food demand and new consumer trend like food delivery services. This new system, however, requires the use of additives to extend the food product quality and safety as well as in maintaining the shelf-life. This study was to prepare the antimicrobial paper from I. cylindrica coated anionic nanocellulose crosslinked cationic to create a system with the ability to actively control microbe growth in the packaging materials. The process involved pulping of I. cylindrica using semi-chemical and soda chemical method. The antimicrobial paper was prepared by printing the pulp suspension in 60 g/m2 grammage in mold followed by the spray of anionic nanocellulose and subsequent soaking of the paper in cationic solution. The results showed the I. cylindrica paper coated anionic nanocellulose crosslinked with H+ and Al3+ cations were successfully produced. The paper produced was also observed to have antimicrobial activity against Gram-negative of E. coli and S. typhi as well as Gram-positive of S. aureus and B. subtilis bacteria. Furthermore, the best coating method was found on antimicrobial paper coated anionic nanocellulose crosslinked Al3+ as evidenced by smoother and compact surface structure.

There is a pressing need around the world to develop novel functional biodegradable materials to separate oil/water mixtures and emulsions completely. Recently, superhydrophilicity and underwater superoleophobicity materials have been attracted attention due to their high efficiency in oil/water separation. However, it is still a challenge to prepare materials that combine oil/water separation and water purification in an environment-friendly way. In this work, biodegradable starch-based nanospheres (SNPs) coated filter paper was prepared in a low-cost, simple, and environmentally friendly manner. The SNPs coating could not only help to change the wettability of the substrate material but also build the hierarchical micro and nano structures which are conducive to separation and purification process. After modification by coating SNPs, the filter paper exhibited excellent performance in a wide range of oil/water mixtures or emulsions separation and the wettability of the filter paper could be regulated by adjusting the pH value. The modified filter paper presented good recyclability after several separation process. Furthermore, the as-prepared filter paper could also remove water-soluble contaminants during the oil/water separation process, thus realizing to combine separation and purification process in one single step. This biodegradable starch-based separating material with good separation performance, stability and recyclability has significant application potential in practical separation and purification process.

Starch and derivatives thereof have proven their usefulness in paper coating processes. Among these derivatives, cationic starch has been widely used in the paper industry as a flocculation, dispersion and ink fixing agent. In another context, nanoscale cellulosic materials have been shown to improve the strength, retention of fillers, the barrier properties of packaging paper products, and printing qualities. This review summarizes the recent studies on the general components used in paper coating, describes the conventional and alternative synthetic processes of cationic starches and nanocellulose, and deals with their current and potential applications in papermaking, focusing primarily on surface treatments. Moreover, environmental applications have been considered to expand the understanding and usefulness of these materials. Further research on modified polysaccharides is encouraged to replace, in a feasible way, petro-based components of coating formulations, and to provide paper surfaces with new properties.

This paper evaluates the environmental impacts of different alternatives for handling of sludge from paper and pulp mills in Sweden, using Life Cycle Assessment (LCA). The common practice of incineration of biosludge with energy recovery followed by landfilling of ash (System A) was compared with the alternative of digesting sludge anaerobically to produce biogas using different digestate residue management options. The digestate produced from anaerobic digestion (AD) was assumed to be incinerated for heat energy recovery in System B or pyrolyzed for biochar production in System C to be mixed with forest soils. The impact categories considered in this work are climate change, non-renewable energy use, mineral extraction, aquatic ecotoxicity, carcinogens and non-carcinogens. The LCA results demonstrate that the two proposed systems significantly reduce the environmental impacts of biosludge management relative to incineration. An 85% reduction in the aquatic ecotoxicity impact is achieved in System C, due to the reduced mobility of heavy metals in biochar relative to ash. System C, on the whole, outperformed the other two, leading the authors to the recommendation that the use of pulp and paper mill biosludge in biogas-biochar production systems is preferable to merely recovering energy from it.

Enormous quantities of bagasse are being used as raw material in agro based large integrated pulp and paper mills. Anaerobic technology is an effective means of biodegradation of organic substance in wastewater and energy production of biogas that can be used as an alternative fuel. This study illustrates the effect of HRT on performance of lab scale hybrid upflow anaerobic sludge blanket (HUASB) reactor on treatment of pulp and paper mill bagasse wash water. The lab scale HUASB reactor was designed for an effective volume of 0.013 m3 with bio balls as packing media at the top of reactor and operated under mesophilic condition. After startup period, the reactor was operated with HRTs of 23.55, 15.98, 12.00, 10.03 and 7.97 h for the average influent COD concentrations of 2503.6 mg/L, 3918 mg/L, 5432 mg/L, 6608 mg/L and 7996 mg/L respectively. The results showed that the maximum COD removal efficiencies and TSS removal efficiencies were in the range of 68.60–92.19% and 89.56–94.66% respectively. The minimum and maximum biogas yield of 0.32 and 0.53 m3/kg CODa were obtained at influent concentration of 2503.6 mg/L and 7996 mg/L respectively.

The advancement in plastic and plastic based products in last two decades has imposed a serious threat to the environment. This has led to an increase in the demand for sustainable and biobased products. Paper and paper products are good alternatives to their plastic counterparts. A key element of paper industry is the raw material (wood, bamboo and nonwood agricultural residues such as bagasse, straws etc.) from which pulp is produced. The pulp is then utilized for production of paper. There are many pulping processes to prepare pulp of various qualities. For fine grade pulp, chemical pulping is used. The chemical pulp is produced by soda, kraft and sulphite pulping processes. However, for newsprint grade pulp, stone ground wood (SW), thermomechanical (TMP), chemi-thermomechanical (CTMP), chemi-mechanical (CMP) or refiner mechanical (RMP) corresponding pulping processes are employed. The method of pulp preparation (pulping process) consumes large amount of energy and chemicals. A new pulping process with electron irradiation using biowaste (bagasse) as a raw material is discussed in this work. Bagasse pulping process is found to reduce about 50% of energy consumption during pulping process. The process is referred to as ‘ECTMP’ (Energy Efficient Chemi-Thermo Mechanical Pulping). The paper produced from aforesaid method also reflected no loss of strength properties with respect of TMP reference pulps. Henceforth, preliminary calculation based on experimental results shows that the proposed bagasse ECTMP process explored the scope of energy savings of the order of 50%.

The recycling of waste paper has been an effective way to achieve the environmental-friendly growth of papermaking industry. Focusing on the mixed-pulping process which has been generally employed, to ensure the required properties of the deinking pulp (DIP) and minimize the purchase cost of waste paper, an intelligent model scheduling the mixing ratio of waste paper was developed in the study. Primarily, driven by the field data of mixing ratio of waste paper and DIP properties, the prediction models of DIP properties were developed by SVM, GA-SVM, and BP-NN algorithms. Subsequently, based on the best prediction model, the scheduling model for the mixing ratio of waste paper was set up by NSGAII algorithm. The experimental results showed that, based on the obtained best BP-NN prediction model of DIP properties, the developed NSGAII scheduling model for the ratio of waste paper could achieve excellent scheduling results under the rigorous constraints and multi-objective. Compared with the previous study, the developed prediction and scheduling models in this study reduced the purchase cost of waste paper by 2.16%, and improved the acceptable proportion of DIP property from 56.07% to 100%.

Soybean-oil-based polymer is a promising bio-based water barrier coating on paper packaging but the application is challenged due to its poor water dispersibility. In this present study, 3-aminopropyltriethoxysilane (APTES) modified nanocrystalline cellulose (NCC) was used to implement a stable dispersion of acrylated epoxidized soybean oil (AESO) in water and thus synergistically improved the water vapor barrier properties after coating on paper. APTES-NCC was successfully prepared, and displayed a better interface compatibility with AESO through the Michael addition reaction. Compared with NCC, APTES-NCC displayed an improved hydrophobicity and wettability with AESO, with an increase of contact angle from 38.0° to 76.4°, and a decrease of interfacial tension from 91.5±3.5 mN/m to 82.9±1.8 mN/m. As an emulsifier, APTES-NCC can be more effectively adsorbed on the oil-water interface to form a more stable emulsion than NCC, with a decrease of AESO droplets size from 4.8 µm to 3.1 µm, and a remarkable improvement in static and centrifugal stability. In rheological measurement, the APTES-NCC/AESO emulsion showed a wider linear viscoelastic region (3.4%), better viscoelasticity and thermal curing properties than that of NCC/AESO emulsion, which further explained that the stability of APTES-NCC/AESO emulsion were improved. Therefore, APTES-NCC/AESO emulsion as a coating on paper cured into a continuous barrier film can effectively improve the water vapor barrier properties of paper, and the water vapor transmission rate (WVTR) of paper can be reduced from 1392.8 g/m2•24h (NCC/AESO emulsion-coated) to 1286.3 g/m2•24h (APTES-NCC/AESO emulsion-coated), both are significantly lower than that of base paper (1926.7 g/m2•24h). CLSM testing showed that APTES-NCC could interact effectively with AESO to forming a tight barrier on paper surface and at the same time, sealing the pores inside the paper to resist water vapor penetration. The high-stable AESO emulsion prepared by APTES-NCC is expected to facilitate the utilization of NCC and AESO as a value-added material in making sustainable barrier packaging.

The application of pulp and paper fibers as reinforcement in thermoplastic composites involves several advantages, such as sustainability, constant fiber quality and high mechanical properties. This work compares three different processing methods for the production of paper-reinforced polypropylene composites. The composites were produced by (i) hot pressing, (ii) injection molding and (iii) a pre-coating process with fiber volume fractions between 10 and 65%. The mechanical properties were investigated by tensile and flexural testing. Furthermore, SEM analysis and porosity determination were carried out. The results were correlated with the according processing method and evaluated towards the highest composite performance. As a result, laminated composites with intact paper layers, showed significantly higher mechanical properties, due to the fiber orientation in the paper sheet and good adhesion between the matrix and the paper fibers. Compounded and injection molded composites showed a high degree of fiber agglomeration and less orientated fibers in the composite leading to reduced mechanical properties.

Conjugated amino acid with nano-biodegradable polymer was applied as ecofriendly and edible coating. Polystyrene sulfate (PSS) was highly investigated with dynamic light scattering (DLS) to measure the particle size and over charge (zeta potential measurements) of nano-polymer system as well as the homogeny of particle distribution in presence and absence of Lysine mixture (AA). In addition, topographical structure of the coating was studied for PSS, AA and conjugated one as well as Fourier transform infrared (FTIR) and Differential Scanning Calorimetry (DSC). Antimicrobial test cleared that the prepared conjugate described as broad-spectrum antibacterial agent as well as antifungal with different concentrations. The hydrophilic active ingredient is absorbed into fiber, distributed homogenously and kept out the fiber loaded with antimicrobial properties over all areas. Tensile strength of the paper sheets coated with uni-layer 200 µ thickness presented good improving in physical and mechanical properties of coated paper sheets as well as gives more fiber condensation according to Scanning Electron Microscope (SEM) topography.

The development of renewable energy sources minimizes the burning of fossil fuels for clean and green environment. Electrochemical energy storage/conversion device pays a way towards sustainable development that concludes an emerging field in the trends of the research community. Prominently, the functional materials with suitable structure and property determine the performance and durability of the devices. In recent times, graphene with its tremendous properties play a major role in electrochemical energy device applications. Meanwhile, the graphene-based electrodes were fabricated by various coating techniques on existing electrodes that utilized for energy device fabrication. Apart from these, it is also fabricated in a paper like a form (self-supported or free-standing) with its remarkable high conductivity, flexibility, robustness and electrochemical behavior which have been nominated for fabrication of flexible energy devices. Paper-like electrodes become an emerging field to fabricate a light-weight and flexible electronic devices for future prospects. Thus, we have summarized a synthetic strategy of graphene paper and its properties that potentially focused on flexible device fabrication in both the energy storage and conversion system. Hence, this review boosts up the forthcoming researchers to enhance the device performance with interrelating free-standing graphene and other host material.

Here we report the construction of CoFe2O4 coating on carbon fiber and the coated paper was used as the interlayer between the separator and cathode of Li-S batteries. The amorphous CoFe2O4 coating was deposited by the industry-oriented spray pyrolysis technique and carbon fiber was completely enwrapped by the coating. Compared to the non-coated carbon fiber, the coated carbon fiber as the interlayer exhibits a superior reversible capacity of 1086 mA h g−1 at moderate current of 0.1C and a low decay rate in the capacity of 0.043% per cycle after 1000 cycles at 1C. Excellent long-term cycling life and rate capacity were also achieved through the coated interlayer. The specially designed interlayer showed remarkable capability to trap effectively the intermediate LPS (lithium polysulfide). The significantly inhibited “shuttle effect” of LPS would give insight into designing and making the interlayer by using new coating materials for enhanced performances of the Li-S batteries.

This review paper encompasses the inclusive approach of lime sludge valorization in construction materials. Research studies based on cement and aggregate replacement by lime sludge concludes that 10–30% lime sludge is gainfully utilized in sustainable concrete and mortar. Additional prospect for lime sludge application in construction material is the production of cement and ceramics. Significant use of lime sludge in combination with supplementary cementitious materials such as silica fume, nanosilica and fly ash is recommended for the production of cement components and ceramics. The recommendations are also suggested in accordance with the outcome of the study.

A kind of wood pulp fiber paper (WPFP) was proposed as candidate for the matrix of desiccant wheel. Silica gel was coated on WPFP by impregnation method and the corresponding coating ratio was obtained and analyzed. Then the thermal conductivity, pore structure and adsorption/desorption performances of WPFP coated with silica gel were tested and analyzed. The results indicated that the WPFP has high coating ratio for silica gel due to its hydrophilic characteristic. The thermal conductivity of WPFP coated with silica gel after the first coating increases obviously compared with raw WPFP and reaches to 0.1292 W/(m⋅K). In addition, the WPFP coated with silica gel after the first coating has high specific surface area and its maximal adsorption quantity for water vapor can be 0.240 g/g. Finally, the DCOP of the desiccant wheel using WPFP as matrix obtained by numerical simulation can be 1.75 under the given working condition that the temperature of regeneration air is set as 90 °C and the inlet condition of process air is set as 34.3 °C and 56.2% RH. It is indicated that the desiccant wheel using WPFP as matrix can meet the requirement of air dehumidification and save energy by 7.35% simultaneously.

The industrial solid waste generation and its stockpile disposal have major environmental consequences. These consequences could be minimized through the solid waste application as a raw material in other industries. The current study focusses on the utilization of lime sludge with boiler ash synthesized nanosilica for production of belite based clinker at relatively lower temperature. Lime sludge was also used in combination with fly ash and boiler ash to check the synthesis of compounds at varying temperatures. Nanosilica was synthesized from pretreated boiler ash through alkali treatment and acid precipitation. The synthesized nanosilica has been characterized for specific surface area, crystallinity, surface functional groups and size. Three different mixtures, containing lime sludge with nanosilica, fly ash, and boiler ash are fired at temperatures ranging from 900 °C to 1200 °C and characterized for the synthesis of belite. Conventionally, belite is synthesized above 1200 °C, whereas the combined application of lime sludge and nanosilica reduces the temperature of belite synthesis to 900 °C without pre calcination or addition of any chemical stabilizer. In the case of lime sludge and boiler ash blend, belite formation takes place at the higher temperature (1100–1200 °C). Anorthite synthesis takes place in case of lime sludge and fly ash blend, due to high percentage of alumina present in fly ash. Lime sludge and nanosilica based belite clinker are used to develop newer cementitious binder. Hydration and strength properties of developed binder proved worthy as building materials. This study will present alternatives for sustainable utilization of lime sludge, fly ash and boiler ash in construction.

The most common negative influences on lignocellulosic materials from biological point of view include invading of microorganisms, which have in humid environments of porous materials favourable conditions for growth and reproduction. The aim of this study was to assess the influence of selected compounds present in essential oils- EOs (linalyl acetate-LA and citral-C) and the accelerated ageing process on the chemical (cellulose degree of polymerization, content of saccharides), mechanical (tensile index) and physical (fibres length distribution) properties of papers. LA and C were evaluated as the compounds with the highest antimicrobial activity and therefore, they were applied into the paper mass in form of their vapours. Paper samples were prepared from five types of material. Chemical changes were evaluated by wet chemical methods, size exclusion chromatography and high performance liquid chromatography, mechanical property according to ISO 1924-2 standard and morphological properties of fibres by using Fiber Tester equipment. In the view of followed properties, the protecting impact of these EOs efficient compounds has a greater importance in their application before the ageing process itself, especially at wood pulp papers and papers produced from sulphate deciduous pulp. The contents of both holocellulose and a cellulose degree of polymerization were significantly correlated with the tensile index of the paper.

A pulp and paper industry generates a large amount of industrial solid wastes, which are mostly wet sludge, basically composed by kaolin and pulp. The National Solid Waste Policy in force in Brazil instituted as mandatory to provide the adequate destination of this material and to improve the costs involved in the process. The purpose of this work was to analyze the feasibility of incorporating sludge from the pulp and paper industry in soil-cement blocks using 10% cement and 90% compensated soil. In the composition of this compensated soil, typical from the region where the research was performed, sand and 5%, 10%, and 15% of waste were incorporated in the clay mass. Compressive strength, water absorption and durability tests were carried out with loss of mass. The results indicate that blocks produced with waste incorporation of up to 10% meet the technical requirements set by the main international standards, enabling them to be used in civil construction and thus contributing to reduce the environmental impacts regarding the waste disposal.

Industrialization and urbanization are the key drivers to threaten the environmental quality and natural resources. Traditionally, pulp and paper industry has been highly reliant on forest based resources for its escalation. Shortage of forest based raw materials, strict environmental regulations and policies have compelled the industry to seek for alternate raw materials for its production. Mills are now focusing on exploring the potential of different agro wastes such as cereal straws and bagasse etc. In present research, sugarcane trash, one of the most abundant agro residues in India, was investigated for its capability in pulping and bleaching. Chemical characterization of sugarcane trash showed that it contains 40.4% cellulose, 33.2% hemicelluloses, 17.4% lignin and 6.45% ash content with 2.76% silica. To cook sugarcane trash with soda pulping method, 14% alkali charge, 15 min time and 162 °C temperature was found to be optimum and pulp of kappa no. 19.8 was prepared that exhibited good strength properties. Bleaching of pulp was carried out using elemental chlorine (Cl2), hypochlorite and chlorine dioxide (ClO2) based sequences. Replacement of Cl2 with ClO2 has significant impact on strength properties and effluent characteristics. Oxygen delignification stage was incorporated prior to ClO2 that resulted in improved optical properties of pulp with noticeable reduction in wastewater load. This paper elaborates the need of using sugarcane trash in paper mills with environment friendly pulping and bleaching processes to combat with the problem of waste management, wastewater load reduction during bleaching and substitute for wood based raw materials in papermaking.

The paper drying process has the highest level of energy consumption in the pulp and paper production process. Analysis and optimization of the energy system during the paper drying process is critical for improving the energy efficiency of the entire paper mill. In the existing model for the paper drying process, the solution requires accurate boundary conditions such as the air temperature and humidity of the pocket area and the cylinder surface temperature, which are very difficult to obtain in the papermaking process. This can result in significant deviations between the model solution and the actual production process. This paper focuses on the single-tier dryer cylinder-based paper drying process that has been widely used with high-speed papermaking machines in recent years. A mathematical model is proposed based on real-time data. The verification via industrial production demonstrates that the proposed model is reliable for the paper drying process. Based on the simulation results, two optimization operations have been proposed. The energy consumption decreases from 1.51 t steam/t paper to 1.44 t steam/t paper, 4.6% of the steam and 1.26 × 106 RMB can be saved for a medium-scale paper mill with the annual production capacity of 105 t paper.

Cellulose is an important component of green plants cell wall and other organisms. Cellulose from plants is mainly used to produce paper. Because of the widespread use of paper throughout the world, it causes the use of wood in large quantities that involves cutting down trees which can lead to negative impacts on ecosystems. Many research studied to find other raw materials that could replace wood and some focused on coconut coir because it contains high amount of cellulose which is enough to use in manufacturing. Coconut pulp is also the residue from coconut. It has 59 % cellulose. This makes it possible to use coconut pulp in paper industry. Paper for chromatography uses fiber from wood as an important component too. So, the purpose of this study was to identify whether cellulose from coconut pulp can replace the original material of chromatography paper. The procedure started from extracted impurity from coconut pulp and used the remaining for making chromatographic paper. Washed coconut pulp and removed residue coconut milk. Boiled clean coconut pulp for 10 minutes and dried in oven at 60 degree Celsius. Remove the residue fat with hexane. Drained hexane and dried in oven at 60 degree Celsius. Extracted cellulose by the soda process. Cellulose yield was 50.85%. Used extracted cellulose as raw material for making chromatographic paper. Tried different amount of cellulose per area of sieve to find the suitable for making paper. The appropriate paper area per extracted cellulose weight was about 81.25 cm2/g. Then trailed the paper used as stationary phase for color separation. The appropriate condition of mobile phase in chromatographic technique (ethyl-methyl ketone, acetone and water) to separate standard colors was also studied. The appropriate ratio of mobile phase which could separate standard solutions was 7:3:3, respectively. The results show that this paper was effective in serving as a stationary phase. This paper has the potential to be developed to use as a substitute material in Bio manufacturing.

Causticizing process of pulp and paper mills, is highly energy intensive and environmentally unsafe. We report environmental friendly electro-electrodialysis (EED) process using in-house prepared cation exchange membranes (CEMs) for NaOH production from green liquor solution (GLS) of agro-based paper mills. Different composite CEMs with varied composition of sulfonated graphene oxide (SGO) incorporated sulfonated poly (ether ether ketone) (SPK) were synthesized. Best optimized CEM (SPK-3 with 3.0 wt% SGO loading) exhibited 1.75 mmol·g−1 cation exchange capacity, 32.01% water uptake, 11.41% swelling ratio, conductivity 0.037 S·cm−1, and 0.97 counter-ion transport number with high alkaline and thermo-mechanical stabilities. Industrial GLS was used for NaOH production by EED at 60 mA·cm−2current density. Optimized SPK-3 membrane produced 1.17 mol·L−1 of NaOH with 61.4% current efficiency (η), and 2.58 kW·h·kg−1 energy consumption (EC) during 4 h of EED process. Under similar operating conditions, pristine (SPK), and commercial CEM (FKB-PK-130), showed inferior performance. Longevity of SPK-3 CEM was assessed with industrial GLS for fifty cycles of EED experiments 4 h duration each. Reported results are promising for sustainable NaOH production from industrial GLS of pulp and paper mills, and provide a resourceful alternate for industrial waste.

Highlights • Numerical simulations of acoustophoresis in pulp flow is conducted. • Parametric study of fiber characteristics, pulp flow regimes and acoustic parameters are conducted. • A feasibility study of industrial acoustophoresis for pulp concentration is performed. • A potential concentration gain of 15% is obtained experimentally., In pulp and paper mills, mechanical processes such as screening and washing are commonly used to remove accumulated solid suspensions and concentrate the pulp. For environmental reasons and to optimize paper production, an emerging challenge is to develop alternative methods to concentrate paper pulp between 3 % and 6 % consistency for which the mixed pulp-water flow is complex. Among the proposed solutions in the literature, solutions based on acoustic levitation, also referred as acoustophoresis, of low-consistency pulp have been demonstrated as a potential solution for efficient pulp concentration and water recirculation. However, no sensitivity analysis on the ultrasound and physical parameters was proposed, limiting the extension to a realistic application. Thus, this paper presents a numerical modeling of acoustophoresis for pulp flow concentration in a pipe. For this purpose, the pulp flow is defined as a pseudo-homogenous fluid with a turbulent Low Re k- ∊ formalism, and the pulp particles are considered spherical and deflected by two acoustic forces, namely the acoustic radiation force and the Stokes drag force, both induced by an ultrasound wave generated along the walls of a circular pipe. The combined action of these two forces in the pulp flow enables to concentrate the particles at the center of the pipe. The influences of particle size and mechanical properties, fluid properties and ultrasound parameters are analyzed within a parametric study to optimize the particle deflection and the pulp concentration. The experimental feasibility of the industrial use of acoustophoresis for the concentration of paper pulp is demonstrated with a concentration gain up to 15 %.

Renewable and bio-based materials have gained great interest on an industrial scale owing to environmental issues. Paper industries also are constantly exploring bio-resources for intrinsic chemico-physical property enhancement of paper and paper products. These bio-resources will potentially increase their cyclability besides making paper compatible beyond traditional uses. Mechanical beating or use of chemical additives or the combination of these methods are widely used to improve critical paper characteristics such as strength, surface smoothness, density, brightness, filler retention, water and grease resistivity etc. These chemical additives as mill effluents are hazardous and have detrimental effect on environment. So, to move ahead of traditional practices, the present review discusses about the production and utility of abundantly available renewable bio-polymers and their products such as starch, cellulose, plant-based proteins, microbial biopolymers, animal-based biopolymers, and natural gums etc. They represent ample prospect in terms of research and development on their functionality and industrial applications.

Pulp and paper mills are known large emitters of air pollution creating potential environmental challenges and human health impacts. This study assesses air pollution and associated impacts from connected pulp and paper facilities which operate in Edmundston, New Brunswick, Canada, and Madawaska, Maine, United States (US). Despite operating within two regulatory jurisdictions on both sides of the international border (in Canada and the US), the mills have exceeded their approvals to operate and national air quality regulations multiple times between 2010 and 2017. Previous studies have linked many types of cancer as well as respiratory and cardiovascular diseases to air pollution emitted by pulp and paper mills, making this an important regional issue in Canada and the US. While potential environmental and community impacts are likely similar on both sides of the international border, emissions from each side are not reported on the other, and few studies have been conducted on either side. Historic and ongoing lack of local epidemiological health and environmental impact studies and recommendations for improvements to mill operations to improve environmental and human health are presented.

This study evaluated the suitability of old corrugated containerboard (OCC) to be upcycled into a high-quality pulp for tissue paper manufacture. The evolution of the physicochemical properties of OCC fibers and their effect on tissue properties were tracked across each stage of two elemental chlorine free (ECF) bleaching sequences. The properties of bleached OCC were compared to those of deinked pulp (DIP), southern bleached softwood kraft (SBSK), and refined OCC unbleached. Both sequences reduced the kappa number from 89 to negligible values and increased brightness from 18.9% to ca. 75% ISO, on average 6.2% ISO units below that of DIP. Overall, bleaching significantly increased tensile index and absorbency rate while having adverse effects on bulk and softness and minor impacts on absorption capacity. The change in properties was correlated to the improved fiber bondability and fiber wettability derived from the lignin removal. Compared to DIP, bleached OCC exhibited a higher tensile index, higher freeness, and similar absorption capacity but lower softness. It also showed higher absorption capacity and similar softness than SBSK but lower freeness at a comparable tensile index. The results indicate that upgraded OCC could be used as an alternative fiber to address the forecasted shortage of high-grade recycled papers in recycled tissue grades or replace virgin fibers in producing virgin tissue grades. In addition, it was determined that refined OCC unbleached could also be suitable for use in tissue grades where high brightness is not an essential product feature.

Solar-reflective thermal insulating coating (SRC) has received great attention because of its desired heat reflective properties and water repellency, which may impart high-value to cellulosic paper via industrially well-established surface coating process. However, the feasibility and possibility of surface application of SRC to cellulosic paper have not been explored. Herein, in the present work, SRC was designed/developed and subsequently used in the surface application to cellulosic paper. Effect of feeding level of titanium dioxide nanoparticles (nano-TiO2) on rheological behavior of the coating, as well as heat-reflective properties, water repellency and mechanical properties of the surface-coated paper was studied. Results showed that the as-obtained coating samples exhibited a notable shear-thinning behavior and displayed strong dependence of rheological behavior on nano-TiO2 amount. Furthermore, the increased nano-TiO2 amount appeared to induce the improved hemispherical emittance of coated paper. The coating weight was also found to exert a positive effect on the hemispherical emittance of coated paper. In addition, it was confirmed that the nano-TiO2 addition played an important role in improving the water repellency and mechanical properties of coated paper.

The biological deinking method using microbial enzymes is quite promising and rather eco-friendly. In this paper, we discuss about the impact of enzymatic deinking of newspaper pulp using ligno-cellulosic (cellulase, xylanase and laccase) and lipolytic enzymes. The individual treatment of paper pulp with enzymes (cellulase/xylanase) could enhance the paper brightness to about 32.86% whereas combinational effect could enhance only about 28.67%. There was a release of chromophores from phenolic and hydrophobic compounds released during the deinking process. Physico-chemical parameters of effluents were also found to be within the standard limits and the metals like iron, lead and zinc were not detected in the enzyme assisted deinking effluent sample. The heavy metals in the paper pulp was found to be reduced after enzyme treatment. The obtained effluent was found have low phytotoxicity and was safe for agricultural applications. Hence, the present report was found to be a suitable enzymatic deinking process which was eco-friendly that results in non-toxic effluents. The method also provides an avenue in water resource recycling within industries.

This work aims at developing sustainable processes for pulp and paper industry by integration of the biorefinery concept to an existing pulp and paper process. A systematic methodology employing a superstructure-based process synthesis approach is employed with support from computer-aided tools to determine potential pathways for a long-term sustainable growth objective. A superstructure of the multi-product biorefinery process network for the pulp and paper industry is developed. It is divided into three sub-networks, a chemical pulping section, a biochemical production section and a black liquor utilization section. Superstructure optimization is performed with the objective to maximize profit to determine optimal integrated networks for three scenarios. The obtained results provide useful insights for further development of the optimal networks as sustainable integrated biorefinery combined with pulp and paper mills.

Dewatering and handling of pulp and paper mill sludge is challenging and often comprises more than half of the overall wastewater treatment costs at a mill. Primary sludge is usually more dewaterable than biosludge (waste activated sludge), and the ratio between both types of sludge largely determines the dewaterability of the sludge mix. This study has quantified the benefits of adding primary sludge to biosludge to enhance the dewaterability in terms of cake solids and filtrate/pressate solids content. Furthermore, the effects of the particle size distribution and the monovalent to divalent cation ratio of the various types of sludge were investigated. Biosludge and three types of primary sludge from a Canadian pulp and paper mill were mixed at various ratios and tested for dewaterability using a Crown Press®, a bench-scale device which simulates industrial belt press dewatering. Results show that after addition of primary sludge at up to 40% mass proportion (dry solids basis) the dewatered cake solids content increased substantially, from 10.4% to 18.7–19.9%, depending on the type of primary sludge added. Further addition of primary sludge led to comparably only small improvements. Primary sludge addition also resulted in decreased total suspended solids (TSS) concentrations in the combined gravity filtrate / Crown Press pressate. Primary sludge content of only 10% in the sludge mix was sufficient to decrease the TSS concentration from 1.8 g/L to 0.2 – 0.4 g/L. The study shows that only less than half of the sludge mix needs to consist of primary sludge, in order to achieve adequate dewaterability. This opens up the possibility of retaining more primary fiber within the pulping process, without compromising downstream sludge dewatering.

The pulp and paper industry, which provides cellulose pulp and paper, bio-based energy and chemicals, is one of the largest energy consumers, greenhouse gases (GHG) and pollutant emitters among manufacturing industries. Although the environmental impact of the pulp and paper industry has been extensively studied, life cycle assessment (LCA) results have not yet reached a consensus. By means of a systematic review and meta-analysis, this article contributes to the quantification and harmonization of the life cycle environmental impacts of pulp making and paper making systems. Based on the screening of 45 cases of paper making and 18 cases of pulp making, we found that 1 t of paper results in about 950 kg carbon dioxide (CO2) equivalent (CO2-eq) GHG emissions on average. However, there are distinct differences between countries and pulp and paper categories. The dominant factor influencing GHG emissions is energy use. In paper making, the pulp making process is responsible for 62% of energy use, 45% of GHG emissions, 48% of acidification potential, and 49% of eutrophication potential. The kg CO2-eq emissions of three different types of pulp were as follows: Kraft, 508 kg CO2-eq/t; chemi-mechanical, 513 kg CO2-eq/t; and recycled pulp, 408 kg CO2-eq/t. Excluding emissions from electricity and steam production, the convergence of carbon emissions is observed within the same categories of pulp. Straw-based pulp caused far more environmental impact than any other type because of the intensive inputs in agricultural activities as well as in the pulp making process. This research highlighted the inconsistencies in functional units, system boundaries, and methodologies and carbon neutrality assumptions in different LCA studies of pulp and paper making. Future studies should focus on the environmental impact of straw-based pulp making, system boundary unification, and calculation of biogenic carbon emissions.

A functional biopolymer-coated paper was prepared by coating a ternary blend of the alginate, carboxymethyl cellulose, and carrageenan with grapefruit seed extract (GSE) for the substitute use of synthetic polymer-coated paper. The microstructure of the surface and cross-section of the coated paper analyzed by field emission scanning electron microscope (FE-SEM) indicated that the biopolymer was compatible with the base paper and filled the pores of the porous fiber to make a smooth-surfaced coating paper. The properties of the biopolymer-coated paper, such as water and oil resistance, water vapor barrier, surface hydrophobicity, and mechanical properties, increased significantly compared with not only the base paper but also commercially used PE-coated paper. The blended biopolymer coating material exhibited strong antibacterial activity against food-borne pathogenic bacteria, Listeria monocytogenes and Escherichia coli, which were destroyed completely within 3 and 9 h, respectively. The packaging test for a minced fish cake packed with the biopolymer-coated paper showed the complete destruction of surface inoculated bacteria in 6–9 days. The biopolymer-coated paper showed a high potential for disposable food packaging applications to increase the shelf-life of packaged food.

Green liquor dregs wastes coming from pulp and paper production are currently disposed in landfills at a huge cost for industry and the environment. In this work, a novel and more sustainable waste management strategy is proposed. Dregs were used for the first time as fine filler in the production of biomass fly ash-based geopolymeric mortars. The influence of the dregs incorporation amount on the fresh (geopolymer kinetics and mortars workability) and hardened-state (mechanical resistance, water absorption and capillary water absorption) properties of the mortars was evaluated. Although dregs incorporation reduce the flow workability (up to 19%), their presence and amount did not significantly alter the geopolymerization kinetics. Additionally dregs-containing mortars exhibited enhanced tensile (up to 71%) and compressive strength (up to 34%), and lower water absorption in comparison with the reference mortar. These results demonstrate the feasibility of using dregs as fine filler in geopolymers production. Moreover the mortars were produced using mainly biomass fly ash waste as aluminosilicate source which further reduces the environmental impact of the pulp and paper industry.

In this work, two pulps, bleached (BP) and raw pulp (RP), derived from the paper production process, were used as precursors of non-activated and activated carbons (ACs). In the case of non-ACs, the production involved either pyrolysis or pyrolysis followed by acid washing. For ACs production, the pulps were impregnated with K2CO3 or H3PO4, and then pyrolysed and acid washed. After production, the materials were physically and chemically characterized. Then, batch adsorption tests on the removal of two pharmaceuticals (the anti-epileptic carbamazepine (CBZ) and the antibiotic sulfamethoxazole (SMX)) from ultra-pure water and from Waste Water Treatment Plant (WWTP) effluents were performed. In ultra-pure water, non-ACs were not able to adsorb CBZ or SMX while ACs showed good adsorption capacities. In WWTP effluents, although ACs satisfactorily adsorbed CBZ and SMX, they showed lower adsorption capacities for the latter. Tests with WWTP effluents revealed that the best adsorption capacities were achieved by carbons produced from BP and activated with H3PO4: 92 ± 19 mg g−1 for CBZ and 13.0 ± 0.6 mg g−1 for SMX. These results indicate the potential of paper pulps as precursors for ACs that can be applied in wastewater treatment.

Primary paper mill sludge (PPMS) is the major waste expelled from the pulp and paper industries contributing soil and water pollution through the recalcitrant organic and inorganic constituents. These pollutants can, however, be transformed into a high-value soil ameliorating material with nominal investment and time. Current study therefore evaluated the potential of rotary drum composting PPMS for 20 days to delineate an environmentally sustainable option. Five trials with proportions of PPMS, cow dung and saw dust: Trial 1 (10:0:0), Trial 2 (8:1:1), Trial 3 (7:2:1), Trial 4 (6:3:1) and Trial 5 (5:4:1) were performed for evaluation of degrading and nutritive ability along with the fate of pollutants for total mass of 150 kg. Trial 4 exhibited highest metabolic activity contributing higher temperature evolution and longer thermophilic phase (10 days) owing to optimum addition of innoculum and nitrogen through the cattle manure. Moreover, degradation of 16.8% organic matter was also best achieved in Trial 4 following up first-order kinetics. Furthermore, BOD, COD and C/N ratio also explains degradation to be maximum in trial 4 (6:3:1) with reduction of 59.3%, 60.1% and C/N ratio from 55.1 to 18 respectively, proving to be the essential determining factors. Phosphorus availability increased by around 67% in trial 4. PPMS can be thus transformed into a potential valued added product and safe for subsequent land application.

Microfluidic paper based microbial fuel cells (μP-MFCs) have gained considerable popularity due to their compact, quick and low-cost fluid manipulation paradigm. Compared to conventional technologies, paper as a substrate with advanced nanomaterial electrode material has many distinct advantages from point-of-care monitoring to energy harvesting. As a result, these have been used and are more popular in a variety of fields, such as health diagnostics, environmental and food quality management. By this encouragement, herein a portable microbial fuel cell as an origami array has been demonstrated using custom carbon electrodes with a modified the transition metal oxide MnO2 nanomaterial. This customized electrode design was first printed using a tabletop PCB inkjet printer where the anode was further modified with synthesized MnO2 nanoparticles. The entire cell was formed by folding the paper along predefined edges where the fuel, Shewanella putrefaciens, was streamed continuously via inherent capillary cation. Various studies, such as morphological, surface catalyst coating, amount loading and volumetric culture optimization experiments, have also been accomplished to find the most appropriate optimum parameter to enhance power conversion efficiency. The developed origami arrayed microbial fuel generated an open-circuit potential (OCP) for two parallel connected MFCs of 0.534 V and a maximum power density of 15.9 μW/cm2 with a maximum current density of 130 μA/cm2. In the end, the harvested power was used by powering the digital watch circuit through the ultra-low DC-DC booster board. Such an MFC origami array, with simple electrode manufacturing and modification process, has a great potential and bright future in Internet of Things (IoT) applications by making multiple stacks where the data can be monitored.

With the rapid development of wearable intelligent devices, low-cost wearable strain sensors with high sensitivity and low detection limit are urgently demanded. Meanwhile, sensing stability of sensor in wet or corrosive environments should also be considered in practical applications. Here, superhydrophobic microcracked conductive paper-based strain sensor was fabricated by coating conductive Ti3C2Tx MXene on printing paper via dip-coating process and followed by depositing superhydrophobic candle soot layer on its surface. Owing to the ultrasensitive microcrack structure in the conductive coating layer induced by the mismatch of elastic modulus and thermal expansion coefficient between conductive coating layer and paper substrate during the drying process, the prepared paper-based strain sensor exhibited a high sensitivity (gauge factor, GF = 17.4) in the strain range of 0–0.6%, ultralow detection limit (0.1% strain) and good fatigue resistance over 1000 cycles towards bending deformation. Interestingly, it was also applicable for torsion deformation detection, showing excellent torsion angle dependent, repeatable and stable sensing performances. Meanwhile, it displayed brilliant waterproof, self-cleaning and corrosion-resistant properties due to the existence of micro/nano-structured and the low surface energy candle soot layer. As a result, the prepared paper-based strain sensor can effectively monitor a series of large-scale and small-scale human motions even under water environment, showing the great promising in practical harsh outdoor environments. Importantly, it also demonstrated good applicability for spatial strain distribution detection of skin upon body movement when assembled into electronic-skin (E-skin). This study will provide great guidance for the design of next generation wearable strain sensor.

The direct coating of graphene sheets obtained by electrochemical exfoliation on commercial paper renders the preparation of highly conductive flexible paper substrate for subsequent deposition of polyaniline (PANi) nanorods via electrochemical polymerization. The deposition of PANi can be well-controlled by adjusting the electrochemical polymerization time, leading to the formation of PANi coated graphene paper (PANi-GP). The as-prepared electrode exhibited high areal capacitance of 176 mF cm−2 in three-electrode system at a current density of 0.2 mA cm−2, which is around 10 times larger than that of pristine graphene paper due to the pseudocapacitive behavior of PANi. In-situ Raman test was used to determine the molecular changes during redox process of PANi. More importantly, all-solid-state symmetric capacitor assembled with two PANi-GP electrodes in a polymer electrolyte delivered an areal capacitance of 123 mF cm−2, corresponding to an areal energy density of 17.1 µWh cm−2 and an areal power density of 0.25 mW cm−2. The symmetric capacitor held a capacitive retention of 74.8% after 500 bending tests from 0 to 120°, suggesting the good flexibility and mechanical stability. These results showed the great promising application in flexible energy-storage devices.

High-capacity electrode materials are critical for portable electronic equipment that requires a high-energy density from lithium ion batteries (LIBs). Many different materials and fabrication methods for such electrodes have been developed for this purpose. Carbon paper coated with recycled silicon powder (CP-RSP) was prepared by coating silicon and pitch powder on the carbon paper, followed by stabilization at 250 °C in air and carbonization at 1000 °C in N2. The CP-RSP acted as both the current-collector and the active material for the anodes of LIBs. Electrodes with 2.5, 5, and 10 wt.% silicon exhibited capacity increases of 94, 129 and 41%, respectively, compared with the silicon-free electrode. The electrode for the CP-RSP with 5 wt. % silicon exhibited an optimal balance between discharge capacity and stability in long-cycle tests under various charging rates.

The present study was conducted to form polysaccharide-based multilayers of cationic starch (CS)/anionic starch (AS), and CS/carboxymethyl cellulose (CMC) on broke chemi-mechanical pulp (BCMP) fibers. It aimed to examine the buildup of CS/AS and CS/CMC polyelectrolyte multilayers (PEM) on the fibers surface, and explore the effects of PEM formation on the properties of the resulting papers. The assembly of PEM was analyzed by using zeta (ζ-) potential, water retention value (WRV), SEM micrographs, and paper properties such as thickness and strength. The results of ζ-potential inversions indicated successful constitution of PEM on the BCMP fiber surface by assembling CS/AS or CS/CMC multilayers. Further, larger ζ-potential variations occurred in depositing CS/CMC PEM, due to more charge of CMC, which presumably formed a layer with greater potential of absorption. Based on the SEM images, the surface of PEM-treated fibers was rougher, compared to the untreated fibers due to the coating with starch. Furthermore, the PEM fabrication resulted in creating fibers with higher degree of WRV, which was consistent with the significant improvement of the sheet strengths. Finally, the strength enhanced papers made from PEM-treated fibers with tensile index of about 37.33 ± 1.47 N m/g vs 22.24 ± 1.23 N m/g or 11.60 ± 0.57 N m/g for the papers made from original CMP and untreated BCMP fibers, respectively, may diminish the challenges related to web breaks in the paper machine conveying BCMP broke fibers.

In the present study, the photodegradation of lignin was studied using TiO2/Polystyrene composite under UV-LED irradiation in a batch-recirculated photoreactor as a supplementary treatment for pulp and paper industries. TiO2/PS composite was synthesized by the solvent-casting method and was characterized by scanning electron microscopy (SEM) and EDX analysis. The 3-level, 3-factor Box-Behnken design was applied to study the effects of main operating parameters and optimization of process circumstances. Besides, COD reduction efficiency, toxicity assays, and reusability were also investigated. The predicted model had R2 and R2adj correlation coefficients of 0.97 and 0.99 respectively, which showed experimental results were very close to the predicted values. Furthermore, under the optimal conditions (reaction time = 72.5, volumetric flow rate = 230 mL/min and lignin = 51.8 mg/L) the lignin degradation efficiency was 93.98%. The maximum COD removal (89%) obtained by 250 mL/min volumetric flow rate and lignin concentration of 50 mg/L after 120 min reaction time. Bioassay using D. Magna exhibited that at the beginning of the process, the toxicity of solution increased but continuously decreasing after then to very low values achieved within 120 min of photodegradation. In addition, the reusability tests demonstrated that the TiO2/PS composite after 5 cycles has a good stability and photocatalytic activity.

Life Cycle Assessment (LCA) has been used to evaluate the life-cycle Greenhouse Gas (GHG) emissions of pulp and paper production, and most previous studies rely on process-based models for specific product types (e.g., printing paper), industry-average data, or information from a few mills. In this work, a data-driven approach is used to quantify GHG emissions intensities of different paper products manufactured by the U.S. mills. Facility-level emission data collected from publically available governmental databases and mill-level production data collected from the private sector were integrated to track the GHG emissions for different product lines and paper products in mills (in total, 165 mills were matched and analyzed). The results highlight the ranges of GHG emissions intensities by different product groups and categories, and can be used as a transparent data source for LCA practitioners, policymakers, and the pulp and paper industry to perform further analysis on carbon accounting and strategic planning for GHG mitigation.

The pulping industry generates vast amounts of bark residues and wastewater treatment sludges, which are combined and stored for varying periods in stacks, often in the open air, prior to utilization for energy via combustion. In order to optimize the storage strategy, the effects of incorporating sludge into bark on heating value and storage-related environmental impacts were investigated in laboratory and outdoor studies. Biological degradation activity was found to be higher in treatments containing 25% sludge (B75S25) and 50% sludge (B50S50) on a fresh mass basis, in comparison with pure bark (B100). Mean monthly dry mass loss was 2.1% (B100), 3.3% (B75S25), and 3.7% (B50S50) in the laboratory and 2.7%, 4.2%, and 4.8%, respectively, outdoors. Sludge addition was found to maintain degradation activity at low temperatures (+ 3°C). Co-storage of sludge and bark led to loss of energy, mainly due to increased loss of biomass and increased moisture content. Overall, biomass moisture content governed the heating value. Cumulative methane emissions over the storage period were higher from the sludge-containing treatments than from pure bark, but emissions of nitrogen-containing gases (N2O and NH3) were negligible throughout. Sludge addition roughly halved the cumulative chemical oxygen demand (COD) of leachate and minimized its concentration of phosphate-P. However, larger amounts of inorganic elements were released to the percolating water from the sludge-containing treatments. Overall, these results indicate that finding alternative uses for the sludge fraction would be beneficial.

In a comparative approach toward treating real pulp and paper wastewater (PPWW), iron-based electro-chemical processes such as peroxi-coagulation (PC), electrocoagulation (EC), electro-Fenton (EF), and ultrasound-assisted PC, EC, and EF were investigated. Sono-peroxi-coagulation (SPC) process showed the best performance for treating the PPWW. The optimal results were achieved under reaction time 50 min, current density 140 mA, and pH = 2.0. Employing the SPC process for treating PPWW under optimal conditions, the best COD removal efficiency (81.7%) was achieved. Also, continuous pH adjustment of the solution, as compared to lack of adjustment, showed a significant influence on COD removal efficiency (more than 10%). The effect of pH on the SPC process and the kind of electro-chemical treatment process utilized, on biodegradability were investigated using BOD/COD ratio and average oxidation state (AOS). In comparison with other electro-chemical processes used in this study, the best biodegradability results were obtained for the SPC process in pH = 2, being 0.4 and 0.94 for BOD/COD ratio and AOS, respectively. SPC process compared to the sono EF process had superior COD removal efficiency and their difference in performance reached near 40%. The influence of sonication was obtained 11.3% and 9% for PC and EF processes respectively. In evaluating the toxicity, the best germination index of Raphanus sativus, irrigated by treated wastewater samples, was achieved 77.9% for the SPC process. The application of US for electrochemical process increased energy consumption and cost of process considerably. The sludge of SPC was also evaluated by Fourier transform infrared spectrum (FTIR), X-ray diffractometer (XRD) and field emission scanning electron microscope (FESEM).

Synthetic styrene-butadiene (SB) and styrene-acrylic (SA) latex binders used in paper coating formulations are common and based on unsustainable petroleum sources. Today's papermaking industry turns towards sustainable substitutes that do not compromise quality, and reduce carbon emission, toxic substance release and waste disposal concerns related to fossil fuel sources. In this study, colloidal starch-based latex nanoparticles that do not require cooking were used for pigment coating and coated on the paper surfaces. The effects of these new biobased binders on the structural and mechanical strength properties, liquid absorption, wetting and surface topography of the paper were investigated and compared with the properties of coated paper that SB latex was used as a coating binder. The results demonstrated that the biobased latex decreases the grammage of paper while maintaining an identical thickness relative to the SB latex samples. The porosity, permeability and roughness of biobased latex are found higher than the SB latex. The biobased latex successfully replaced SB latex at 1:1 ratio and enabled an equivalent of bursting, tear, tensile strength and structural properties.

This study considered the possibility of reducing the environmental footprint of paper and pulp industry by producing bioenergy from paper sludge by using process wastewater instead of fresh water, and reclaiming water trapped in paper sludge. Experimental studies are conducted with streams from three different pulp and paper mills (virgin pulp mill (VP), corrugated recycling mill (CR), tissue printed recycling mill (TPR)) for sequential bioethanol and biogas production with simultaneous reclamation of water from paper sludge (PS). Total energy yields of 9215, 6387, 5278 MJ/tonne dry PS for VP, CR and TPR, respectively, were obtained for ethanol-biogas production. Virgin pulp paper sludge gave the highest yield for ethanol and biogas in stand-alone processes (275.4 kg and 67.7 kg per ton dry PS respectively) and also highest energy conversion efficiency (55%) in sequential process compared with CR and TPR. Energy and environmental case study conducted on virgin pulp mill has proven the possibility of using paper sludge bioenergy to reduce energy demand by 10%, while reclaiming 82% of the water from the PS, reducing greenhouse gas emissions (GHG) by 3 times and producing solids suitable for land spreading.