The circular economy requires advanced methods to recycle biomass into value-added materials, such as lignin extraction and modification. Here, we review lignin valorization with focus on lignin ...extraction from biomass, lignin modification, and applications in medicine, cosmetics, environment and agriculture. Lignin extraction can be done by alkaline hydrolysis, kraft pulp method, glycerolysis, single and binary solvent systems, and ionic liquids. Lignin modification includes functionalization, preparation of lignin graft polymers and lignin nanoparticles, and depolymerization. Applications comprise tissue engineering and wound healing, substance carriers for delivery, coatings, natural sunscreen and surfactants.
Although pulping processes from wood are well-cemented technology, the emergence of bio-based nanotechnology, as well as the increase in concern about the environmental impact that these processes ...can have, calls for a reevaluation of the impacts that the traditional pulping methods have on the surfaces of the fibers and how variances will then affect the generation and properties of the nanocellulose materials, that will then impact the different applications that can be derived from them. Since literature tends to focus on one method and then characterize it, the aim of this review is to discuss the properties that have been reported of different fibers and nanofibers depending on the wood source, the chemical pulping method selected (kraft or sulfite methods), and the bleaching or lack of it and then compare the effects that these can have in properties such as crystallinity, chemical composition, surface charge, and functional groups present on the surface.
For economic reasons, increasing the use of various fibrous pulps with high lignin contents—i.e., chemothermomechanical pulp (BCTMP and CTMP), thermomechanical pulp (TMP), and semichemical pulp—is ...desirable. The relatively good quality and increased efficiency of these pulps make them attractive paper semi-products. In particular, they could alleviate the severe shortage of paper semi-products. Although mechanical pulp and semichemical pulp are achieving increasing quality with substantially increased wood efficiency, their production is often characterised by high consumption of electricity to defibre chips or refine high-lignin-content fibrous pulps. Technological, environmental, and economic evaluations of the manufacture and application of increased efficiency cellulose pulps that take into account potential profits from increased cellulose pulp efficiency and losses due to energy costs and degradation in the properties of the resulting paper are relevant and essential to paper mills. This article reports such an analysis. The authors have analysed the usable properties of ten cellulose pulps with various degrees of digestion and identified the optimum pulp that yields the optimum product properties, considering the yield; pulp refining time, which determines the cost of paper manufacture; and strength properties of the obtained paper.
Pulp and Paper Mill Effluent Management Elnakar, Haitham; Buchanan, Ian D.
Water environment research,
October 2018, Letnik:
90, Številka:
10
Journal Article
Recenzirano
Odprti dostop
This is a review of literature published in 2017 related to the prevention of water pollution by or recovery of beneficial materials from wastewater produced in the pulp and paper industry. This ...review includes the following main sections: cleaner production, biological treatment, and physico-chemical treatment.
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The pulp and paper industry is in active development in the northern regions. The ecosystems of northern rivers are less capable of biological self-rinsing and are more sensitive to anthropogenic ...pollution. Assessment of the pollution of waterbodies is important in order to control the conservation of their bioresources. This article provides a literature review that illustrates the main impacts of wastewater of the pulp and paper industry on aquatic ecosystems. It will be useful for specialists working with monitoring systems. This paper discusses examples of the impact of wastewater of the pulp and paper industry on aquatic organisms at different levels of organization, from the molecular to the ecosystem levels. The review describes the responses of aquatic zoocenoses (zooplankton and zoobenthos) to pollution and the effects of specific substances that enter waterbodies from the effluents of the pulp and paper industry. The paper analyzes information about the transformation of bottom sediments of rivers and lakes in the wastewater zone. An overview of data is given, and the impact of thermal pollution is evaluated. This type of pollution often characterizes industrial wastewater. One of the large rivers in the European part of Russia is the Vychegda River. The rivers in its basin are important in the Komi Republic. Therefore, monitoring of the condition of the communities of aquatic organisms that inhabit it is an urgent task. This paper presents the results of hydrobiological observations carried out on the Vychegda River in the 1980s. At that time, changes in the communities of aquatic organisms in the area of pulp and paper industry were observed.
Anaerobic treatment of sedimented fibers collected from bottom of a bay that had been receiving pulp and paper mill wastewater for about 70 years were studied for the first time in semi-continuously ...fed continuously stirred tank reactors (CSTR). Anaerobic treatment of the fiber sediment was shown to be feasible, without dilution and with nitrogen and buffer supplement, at organic loading rates (OLR) up to 2.5 kg VS/m3d and hydraulic retention times (HRT) of 60 d resulting in methane yields of 201 ± 18 L CH4/kg VS. Co-digestion of sedimented fiber with sewage sludge at an OLR of 1.5 kg VS/m3d and HRT of 20 d resulted in a methane production of 246 ± 10 L CH4/kg VS. The techno-economic feasibility of mono and co-digestion process together with several case dependent factors such as maximum operable OLR, digestate utilization needs to be evaluated before making further conclusions for larger scale remediation applications.
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•Anaerobic treatment of old pulp and paper sedimented fibers in CSTRs is feasible.•At least OLR 2.5 kg VS/m3.d and 60 d HRT with 201 ± 18 L CH4/kg VS are achievable.•Nitrogen and buffer addition needed to ensure methanogenesis.•Co-digestion of fiber with sewage sludge produce 262 ± 19 L CH4/kg VS methane.•4 AD of 5000 m3 needed to treat the entire 1.5 million m3 sediment in 10 years.
As a byproduct of the industrial synthesis of phosphoric acid, there was a large quantity of phosphor gypsum (PG) accumulation, which needs enormous storage space and endangers the environment. The ...preparation of calcium sulfate whisker (CSW) from waste PG could solve the large amounts of PG accumulation and substitute the plant-based pulp fiber, reducing the pollution of wastewater in paper and pulp industries. In this work, the CSW, which length could reach 230 μm, was fabricated from the PG in a glycerol-water solution. It could be found that the glycerol-water volume ratio of 4:6 was the best ratio that could reduce the water activity and accelerate the phase transition from calcium sulfate dihydrate (CSD) to CSW. Meanwhile, the CSW, after calcination, could prepare the anhydrous calcium sulfate whisker (ACSW) with low solubility in water; when the ACSW substitution rate reached 50%, the property of the complex paper could still satisfy the standard of mechanical and optical for offset book paper.
A large volume of food is being wasted every year, while the pulp and paper industry also generate a large amount of solid wastes on a daily basis, causing environmental challenges around the world. ...Dry anaerobic digestion (AD) of these solid wastes is a cost-effective method for proper management. However, dry digestion of these waste streams has been restricted due to their complex structure, the presence of possible inhibitors and inappropriate operating conditions. In light of this fact, dry digestion of food waste (FW) and paper wastes (PW) was conducted at different total solid (TS) concentrations of reactor mixtures of 14%, 16%, 18% and 20% TS, corresponding to substrate to inoculum (S/I) ratio of 0.5 and 1; investigating the optimum operating conditions for effective dry digestion of these complex wastes. The highest methane yields of 402 NmlCH4/gVS and 229 NmlCH4/gVS were obtained from digestion of FW and PW, respectively at 14%TS corresponding to an S/I ratio of 0.5. Increasing the S/I ratio from 0.5 to 1 and thereby having a TS content of 20% in the reactor mixtures was unfavorable to the digestion of both substrates.
This study aims to highlight the energy improvement potentials of Pakistan's paper sector that is one of the most energy intensive industries by benchmarking its specific energy consumption (SEC) to ...produce a similar grade of paper. To address issues such as the lack of indicators for energy efficiency benchmarking in Pakistan's paper industry. Furthermore, energy saving potential was estimated by comparison with paper industries in the United Kingdom and Canada, where energy benchmarks have already been established and data on energy benchmarking is readily available. This study energy consumption data accounts for 75% of the total energy utilized in Pakistan's paper industry and is compared with the energy consumption of the UK and Canada paper sectors where the most up-to-date energy-saving techniques are used. The calculation shows that when compared to the paper industries in the UK and Canada, Pakistan's paper industry utilizes an additional 1.3 MWh of energy for every tonne of paper produced. With a total yearly paper production of 314,549 metric tonnes, this equates to an additional 408,913 MWh of overall annual energy use. It is concluded that if the proposed energy benchmark in this study is applied within the country's mill comparison, savings of 16.4% of overall energy consumption in the Pakistan paper sector can be achieved. It is also shown that the implementation of the best available techniques used in the UK and Canada in Pakistan's paper sector could result in a potential energy saving of 43% of the total energy consumed by this sector.
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Triterpenic acids (TTAs), known for their promising biological properties, can be found in different biomass sources and related by-products, such as
bark, and have been extracted using organic ...volatile solvents such as dichloromethane. Recently, deep eutectic solvents (DES) have been identified as promising alternatives for the extraction of value-added compounds from biomass. In the present work, several hydrophobic DES were tested for the extraction of TTAs from
bark. Initial solubility studies revealed that DES based on menthol and thymol as the most promising solvents for these compounds given the highest solubilities obtained for ursolic acid (UA) at temperatures ranging from room temperature up to 90 °C. Accordingly, an eutectic mixture of menthol:thymol (1:2) was confirmed as the best candidate for the TTAs extraction from
outer bark, leading to extraction yields (weight of TTA per weight of biomass) at room temperature of 1.8 wt% for ursolic acid, 0.84 wt% for oleanolic acid and 0.30 wt% for betulinic acid. These values are significantly higher than those obtained with conventional organic solvents under similar conditions. The results obtained using these DES are promising for the recovery of TTAs for nutraceutical and pharmacological applications, while reinforcing the potential of DES as promising solvents to be applied in biorefinery processes.
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