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Green liquor dregs (GLD) is an alkaline by-product from the pulp and paper industry with a pH between 10 and 14. Today most of the produced GLD in Sweden is landfilled. As a fine-grained alkaline material, it might be possible to use it for acid-generating mining waste remediation. To increase the utilization, quality characteristics and environmental performance need to be determined. In this study samples were collected 5 times from 16 mills during a period of 2.5 years, and were characterized by analyzing dry matter content, loss on ignition (LOI) 550 °C and LOI 950 °C, elemental analysis, pH, electrical conductivity, and calorific value. The results were then evaluated using multivariate statistics (PCA) as well as being compared to other studies and Swedish till. The results show that even if GLD is heterogenous (both within a mill and between different mills) trends can be seen for samples from most mills. When samples do stand out, it is predominately related to the same four mills. Most of the studied parameters showed characteristics favorable for use as a remediant; however, TOC, sulfur, and some of the elements require further study. In general, this study concludes that GLD can be a viable option for the remediation of small orphaned sulfidic mining sites and thus worthy of further studies on the interaction between GLD and acidic mining waste.Overall, GLD can be a good alternative for cost-effective remediation of smaller orphaned mining sites. It is readily available in large quantities, has the qualities needed for remediation of many orphaned acidic mining sites, and can often be locally sourced near the mining site. The use of GLD for mining site remediation is likely also a more sustainable method compared to traditional remediation methods., (© 2024. The Author(s).)

Paper mill sludge (PMS) is featured with a high content of cellulose and hemicellulose, and using its characteristics to make paperboard can achieve a high-value utilization of PMS, which has attracted growing interest. In this study, currently prevalent landfill, incineration technologies (generating heat and electricity by incineration), and three paperboard technologies (medium density fiberboard, pulp board, and corrugated paper) were evaluated and compared via life cycle assessment (LCA) and life cycle costing (LCC) methods. LCA results show that the PMS-to-pulp board outperforms others with an energy conservation and emission reduction (ECER) value of - 2.86 × 10 -8 , while the landfill exhibits the highest overall environmental impact with an ECER value of 4.80 × 10 -9 . LCC results reveal that the PMS-to-pulp board delivers the highest economic profit with $257.357, while the landfill is the lowest with $ - 35.63. The PMS paperboard technologies are more economically friendly than the incineration technologies due to additional electricity/steam consumption during the PMS pre-drying process in incineration. In addition, different scenarios were set up to explore national GHG emission reduction potential by increasing paperboard technologies application rate and reducing the proportion of landfill and incineration. The scenario analysis suggests that replacing 90% of landfill and incineration ratio with PMS paperboard technologies could tremendously improve the overall emission reduction performance with - 9.08 × 10 10 kg CO 2 eq. This result indicates that the PMS treatment technology transformation has a significant favorable impact on the achievement of the "carbon neutrality" target., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

To overcome the human and animal survivability risk, sustainable development is the only option on earth that can be achieved through the maximum use of renewable environmental resources. Recycling of waste paper is an emerging waste management approach to conserve natural resources. Herein, we studied enzyme-mediated process to recycle the xerographic paper by using the crude fungal extract from indigenously isolated fungi identified as Aspergillus assiutensis. The fungal enzyme cocktail has been characterized for the production of multiple enzymes namely cellulase, amylase, xylanase, pectinase, and protease. All these enzymes have pH optima in the acidic range and except cellulase and all the enzymes are stable from 10 to 80 C. In the zymogram analysis, pectinase, xylanase, amylase, and cellulase were detected at 68 kDa, ~ 54 kDa, 38 kDa, and 30 kDa, respectively. Also, the presence of protease was confirmed by the clear zone at 68, 31, and 16 kDa. A 26% decrease in the kappa number and reduction in Hex A of the pulp was observed on the treatment of the pulp with enzyme as compared to the control pulp without any treatment. The physical and chemical properties of the pulp were also improved by enzyme-mediated pulping as compared to the control The physiochemical parameter of the effluent like TDS was reduced (397 ppm) significantly in comparison to chemical deinking process and it was within the permissible limit. BOD and alkalinity were reduced when the enzymes and chemical dosage were used in combination. These results indicate that chemi-enzymatic deinking is most promising to reduce or remove the pollution parameters including ink and this approach can be used in the paper and pulp industry for sustainable development., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

To ensure the safety of food contact materials, a liquid chromatography method was established to determine the migration of formaldehyde in paper packaging with various food simulants (10%, 25%, 50%, 75%, and 95% ethanol by volume) and to investigate the migration behavior of formaldehyde after various durations and with various materials. The results showed that the method has good linearity with a correlation coefficient of R 2  > 0.9990, a detection limit of 0.0011 ~ 0.0027 mg L -1 , and a spiked recovery of 89.7 ~ 103.2% in the range of formaldehyde determination; the migration of formaldehyde in all six paper contact materials showed a trend of gradual increase with time until equilibrium was reached. At the same time and temperature, the migration of formaldehyde in paper packaging was the highest in low-concentration ethanol. With the same food simulants and materials, the maximum migration of formaldehyde in printed materials was greater than that in nonprinted materials; with different materials and the same food simulant, the thickness value was higher, with the use of water-based ink as a printing material, and the maximum migration value of formaldehyde by offset printing technology was low., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Globally, per- and polyfluoroalkyl substances (PFAS)-related research on paper products has focused on food packaging with less consideration on the presence of PFAS at different stages of the paper recycling chain. This study analysed the prevalence of PFAS in paper grades used for the manufacture of recycled paperboard. The presence of PFAS was attributed to the use of PFAS-containing additives, consumer usage, exposure to packed goods as well as contamination during mingling, sorting, collection, and recovery of paper recycling material. Q Orbitrap mass spectrometry was used to analyse the paper samples after accelerated solvent extraction and solid phase extraction. The distribution and possible propagation of 22 PFAS were determined in pre-consumer, retail and post-consumer paper products. Post-consumer samples had the highest combined average concentration (ΣPFAS) at 213 ng/g, while the ΣPFAS in retail (159 ng/g) and pre-consumer samples (121 ng/g) was detected at lower concentrations. This study showed that waste collection and recycling protocols may influence PFAS propagation and that measures must be developed to minimise and possibly eliminate exposure opportunities., (© 2024. The Author(s).)

Recent research has indicated high economic and environmental costs of human paper usage. Technologies have been developed to reduce consumers' paper use behavior, including mechanical dispensers that institute a delay between opportunities to obtain each consecutive unit. However, there is no empirical evidence that these dispensers or delays reduce paper use. In Experiment 1, implementing a delay between paper-unit deliveries using mechanical dispensers in a university cafe resulted in a significant decrease in units per person, material per person, and cost per person, compared to free-access dispensers. In Experiment 2, a relatively long delay was more effective than a short delay in reducing paper consumption in a laboratory experiment using mechanical dispensers. These results indicate that delays could be used to decrease paper use in many contexts on a larger scale. More research is necessary to determine the underlying behavioral mechanisms responsible for the observed reduction and the cost-benefit relationship under different circumstances. Keywords Reinforcement delays * Paper dispensers * Sustainability * Climate change * Behavioral nudges, Sustainability is rooted in human behavior, which is controlled by variables that can be manipulated (Baum, 2005; Skinner, 1953; Ylek & Steg, 2007). Verbal strategies (e.g., requests, education, information) to [...]

The economic development of a country directly depends upon industries. But this economic development should not be at the cost of our natural environment. A substantial amount of water is spent during paper production, creating water scarcity and generating wastewater. Therefore, the Pollution Control Board classifies this industry into red category. Water is used in different papermaking stages such as debarking, pulping or bleaching, washing, and finishing. The wastewater thus generated contains lignin and xenobiotic compounds such as resin acids, chlorinated lignin, phenols, furans, dioxins, chlorophenols, adsorbable organic halogens (AOX), extractable organic halogens (EOCs), polychlorinated biphenyls, plasticizers, and polychlorinated dibenzodioxins. Nowadays, several microorganisms are used in the detoxification of these hazardous effluents. Researchers have found that microbial degradation is the most promising treatment method to remove high biological oxygen demand (BOD) and chemical oxygen demand (COD) from wastewater. Microorganisms also remove AOX toxicity, chlorinated compounds, suspended solids, color, lignin, derivatives, etc. from the pulp and paper mill effluents. But in the current scenario, mill effluents are known to deteriorate the environment and therefore it is highly desirable to deploy advanced technologies for effluent treatment. This review summarizes the eco-friendly advanced treatment technologies for effluents generated from pulp and paper mills., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

China's pulp and paper industry (CPPI) has been always the main carbon emission source in recent years. However, the analysis on influencing factors of carbon emissions from this industry is insufficient. To address the issue, the CO 2 emissions from CPPI are estimated in the period of 2005-2019, the driving factors of CO 2 emissions are investigated by the logarithmic mean Divisia index (LMDI) method, the decoupling state of economic growth and CO 2 emissions is determined by Tapio decoupling model, and finally, future CO 2 emissions are predicted under four scenarios by the STIRPAT model to explore the potential of carbon peaking. The results show that CPPI exhibits a rapid increase and a fluctuating downward trend in CO 2 emissions during the period of 2005-2013 and 2014-2019, respectively. The main promoting and inhibiting factors to the increase of CO 2 emission are per capita industrial output value and energy intensity, respectively. There are five decoupling states of CO 2 emissions and economic growth during the study period, and the CO 2 emissions exhibit a weak decoupling state with the industrial output value growth in most years of the study period. It is very difficult to realize the carbon peaking goal by 2030 under the baseline and fast development scenarios. Therefore, efficient low carbon and strong low-carbon development policies are necessary and urgent for the realization of carbon peaking goal and the sustainable development of CPPI., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

One of the paper industry's major focuses is shifting toward eco-friendly paper production. Chemical-based bleaching of pulp, which is widely used in the paper industry, is a highly polluting step. Replacing it with enzymatic biobleaching is the most viable alternative to make the process of papermaking greener. Enzymes such as xylanase, mannanase, and laccase are suitable for the biobleaching of pulp, which involves the removal of hemicelluloses, lignins, and other undesirable components. However, as no single enzyme can achieve this, their application in industry is limited. To overcome these limitations, a cocktail of enzymes is required. A number of strategies have been explored for the production and application of a cocktail of enzymes for pulp biobleaching, but no comprehensive information is available in the literature. The present short communication has summarized, compared, and discussed the various studies in this regard, which will be highly useful to pursue further research in this regard and make the process of papermaking greener., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The production of paper is a key component for global civilization. Around 300 million tonnes of paper are produced every day globally, with matured pulpwood being the major contributor. Due to rising demand for paper and the depletion of available wood resources, researchers are now focused on finding alternative non-wood resources that are suitable for pulp and paper production. The current study aims to produce eco-friendly and biodegradable paper using a combination of Eichhornia crassipes (water hyacinth) and dried flowers. Water hyacinth is considered as a lignocellulose plant which contains 57% lignocellulose, and dried flower contains 40% cellulose, which is the prime source for paper production. Various sections of water hyacinth, including wet and dry petiole, leaves, and root, were blended with dried flowers through the soda process. Then, the physical properties and FTIR analysis was carried out to identify the quality of the paper produced. The paper produced from root and dried petiole has a lower thickness (1.0 mm and 0.5 mm) than other mix proportions. The opacity of the leaves was found to be 0.5% (light passing) and for the root 0.7% (light passing). Also, the dry petiole and root paper have a good dry tensile strength of 1.30Kpa and 1.20Kpa, respectively. Hence, paper made from dry petiole and root was found to be efficient and suitable for the paper industry., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Apart from protecting the environment from undesired waste impacts, wastewater treatment is a crucial platform for recovery. The exploitation of suitable technology to transform the wastes from pulp and paper industries (PPI) to value-added products is vital from an environmental and socio-economic point of view that will impact everyday life. As the volume and complexity of wastewater increase in a rapidly urbanizing world, the challenge of maintaining efficient wastewater treatment in a cost-effective and environmentally friendly manner must be met. In addition to producing treated water, the wastewater treatment plant (WWTP) has a large amount of paper mill sludge (PMS) daily. Sludge management and disposal are significant problems associated with wastewater treatment plants. Applying the biorefinery concept is necessary for PPI from an environmental point of view and because of the piles of valuables contained therein in the form of waste. This will provide a renewable source for producing valuables and bio-energy and aid in making the overall process more economical and environmentally sustainable. Therefore, it is compulsory to continue inquiry on different applications of wastes, with proper justification of the environmental and economic factors. This review discusses current trends and challenges in wastewater management and the bio-valorization of paper mills. Lignin has been highlighted as a critical component for generating valuables, and its recovery prospects from solid and liquid PPI waste have been suggested., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Paper for recycling has become a promising raw material for the pulp and paper industry due to its low cost and because it is conducive to sustainable development. Unfortunately, recycled paper contains a high volume of printed paper that is difficult to deink, which restricts its applications. Flotation deinking plays an essential role in the product quality and process cost of wastepaper recycling. This study was performed to evaluate the deinkability of environmentally friendly offset inks by flotation deinking. For this purpose, three mineral oil free series of four-color inks, namely, hybrid light emitting diode ultraviolet (LED-UV), LED-UV, and vegetable oil-based inks, were printed on white lightweight coated papers under laboratory conditions. The deinking methodology involves repulping, deinking agent treatment, flotation, hand sheet making, and evaluation of the produced hand sheets. The obtained results indicated that the hybrid LED-UV prints had the best deinkability. After flotation deinking, the deinking efficiency and the whiteness of the hybrid LED-UV ink increased by 58.1% and 47.6%, respectively. LED-UV ink had a 46.9% increase in the deinking efficiency and a 37.0% increase in the whiteness of the hand sheet. The deinking efficiency of the vegetable oil-based ink was the lowest, at 42.1%, and the whiteness of the hand sheet increased only by 23.8%. The particle size distribution analysis demonstrated that the hybrid LED-UV four-color ink exhibited a larger value of the average particle size than the two other. Scanning electron microscopy revealed that the hybrid LED-UV ink particles on the surface of the fibers were the least abundant after deinking. The physical strength properties of the hand sheets, including tensile index, folding resistance, and interlayer bonding strength of the hybrid LED-UV, LED-UV inks, and vegetable oil-based inks, increased., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A simple one-step drawing for the cost-effective fabrication of microfluidic paper-based analytical devices (µPADs) for the determination of phosphate content in water and fertilizer samples is presented in this paper. The hydrophobic barrier of µPAD was patterned using a 2-mm tip marker pen using a transparent acrylic sheet template. The molybdenum blue reaction using ascorbic acid as a reducing agent was used. A pre-concentration step of samples is proposed to improve the sensitivity of the measurement. The blue complex produced on the µPADs was recorded using a smartphone camera. The color intensities (red, green, blue and gray) were analyzed using ImageJ program. The proposed µPAD method provides a linear calibration range from 0 to 100 mg L -1 P. The limit of detection (LOD) was found to be 0.7 mg L -1 P with a precision of 3.1%RSD for 50 mg L -1 P (n = 10). The proposed method was successfully applied to the determination of phosphorus contents in water and liquid chemical fertilizer samples. The results obtained from µPAD agreed with a spectrophotometric method using paired t test at a 95% confidence level., (© 2022. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

The adverse effect of ultraviolet (UV) radiation on human beings has sparked intense interest in the development of new sensors to effectively monitor UV and solar exposure. This paper describes a novel low-cost and flexible graphene oxide (GO)-based paper sensor capable of detecting the total amount of UV or sun energy delivered per unit area. GO is incorporated into the structure of standard printing paper, cellulose, via a low-cost fabrication technique. The effect of UV and solar radiation exposure on the GO paper-based sensor is investigated using a simple color change analysis. As a result, users can easily determine the amount of ultraviolet or solar energy received by the sensor using a simple color analysis application. A neural network (ANN) model is also explored to learn the relation between UV color intensity and exposure time, then digitally display the results. The accuracy for the developed ANN reached 96.83%. The disposable, cost-effective, simple, biodegradable, safe, and flexible characteristics of the paper-based UV sensor make it an attractive candidate for a variety of sensing applications. This work provides new vision toward developing highly efficient and fully disposable GO-based photosensors., (© 2022. The Author(s).)

Pulp and paper industries are very important for developing the Brazilian economy. During production processes, many effluents are generated with high polluting potential. The objective of this study is to conduct an extensive literature review on the characteristics of effluents and treatment forms adopted by Brazilian mills in this industrial sector. Most consulted studies address raw (without treatment) and secondary (after biological treatment) effluents, considering their main characteristics like pH, chemical and biochemical oxygen demands (COD and BOD, respectively), color, solids, organochlorines, toxicity, estrogenic activity, and phenols. Raw effluents differ considerably in composition, depending on the type of paper produced, the pulping process employed, and other steps, like pulp bleaching. Raw effluent characteristics indicate that this effluent cannot be directly disposed of into water bodies, because it does not comply with federal and state disposal standards. Secondary effluents normally comply with Brazilian legislations, although some studies have reported COD and total phenol concentrations higher than disposal standards, suggesting that additional treatments are necessary. Treated effluent reuse was verified in some Brazilian mills, while its disposal in eucalyptus plantations has been considered a promising alternative for irrigation purposes., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Nowadays, the paper industry supplies its required fibers either from primary fibers, including wood and plants, or waste papers, called secondary fibers. One of the most challenging recycling processes is deinking of papers digitally printed with electrophotographic ink. In order to produce optically high-quality paper from recycled waste papers, deinking step is required at the desired levels. In this work, the environmentally friendly green enzymatic deinking of printed paper was modeled and optimized via an innovative approach called artificial intelligence method. The effect of treatment temperature, treatment time, and enzyme dosage on mechanical properties (tensile and burst strengths) as well as optical properties (whiteness and brightness) of handsheet was investigated. The developed code can appropriately learn the non-linear behavior of deinking process, and make decisions according to the pattern constructed intelligently. Finally, multi-objective optimization at the specified treatment temperature, treatment time, and enzyme dosage was performed to identify the best conditions for enzyme-deinked handsheet (maximized mechanical and optical properties)., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The membraneless-gas separation microfluidic paper-based analytical device (ML-GS μPAD), consisting of donor, spacer, and acceptor layers, was developed to monitor total ammonia in fish pond water. The principle of the analysis involved the addition of sodium hydroxide solution to the sample zone in the donor layer containing ammonia/ammonium, and the produced ammonia gas diffuses through the spacer to the detection zone in the acceptor layer containing red rose extract to produce a color change from pink to blue corresponding to the ammonia/ammonium concentration. Under optimum conditions, the proposed method provided good linearity of ammonia in the range concentration of 0-100 mg L -1 (R 2  = 0.9993) with LOD and LOQ of 2.25 and 7.51 mg L -1 , respectively. This method was successfully applied to fish pond water samples without significant influence of interfering compounds with recoveries in the range of 103-110%, indicating good selectivity and accuracy of the proposed method., (© 2022. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

In this work, we present for the first time, a simplified fabrication of a laminated paper-based analytical device (LPAD) with a free-mobile app, Palette Cam, for image analysis. A filter paper is cut in a rectangular shape (9 × 3 cm) and placed between a top laminating sheet with punched holes and a bottom laminating sheet. The holes allow accessibility of liquid on the paper. Thermal lamination is then employed to complete the fabrication of LPAD. Our simplified design reduces a tedious alignment of small pieces of paper to the holes. We demonstrated the LPAD with an analysis of salicylic acid in pharmaceutical products. Each 4 μL of ferric reagent and sample was dispensed on the LPAD. Smartphone was used to capture images. The RGB (red green blue) color intensity from the Palette Cam was converted into a logarithm color ratio. Our LPAD is simplified, cost-effective and able to be a portable device., (© 2022. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

Early and on-site detection of environmental contaminations and physicochemical parameters of seawater is increasingly preferred to guarantee hazard minimization in many settings. In this paper, we describe a combination of microfluidic paper-based sensors (µPADs) and an Android-based smartphone application (App) for simultaneous on-site quantification of phosphate (PO 4 -P), silicate (SiO 3 -Si) and nitrite (NO 2 -N) in coastal seawater samples. The developed App can on-site capture, process, and quantify the µPAD colorimetric outputs. This App uses an image processing algorithm for quantifying color intensity and relating the RGB components to the analyte concentrations. The GPS-tagged data can be stored on the smartphone or sent via social networks. The significant factors affecting the detection of the analytes were optimized using Box-Behnken design. Under optimized parameters, the proposed method presented the linear ranges between 5 and 100 µg L -1 for phosphate (R 2  = 0.9909), 5 to 100 µg L -1 (R 2  = 0.9819) for nitrite and 10 to 600 µg L -1 (R 2  = 0.9933) for silicate. The LODs of the method for detection of phosphate, nitrite and silicate were 1.52 µg L -1 , 0.61 µg L -1 and 3.74 µg L -1 , respectively. The device was successfully used to simultaneous analyze and map the PO 4 -P, SiO 3 -Si and NO 2 -N of Bushehr coastal seawater samples (Iran). The results were confirmed by the lab-based conventional colorimetric methods using spectrophotometer., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The pulp and paper industry discharges massive amount of wastewater containing hazardous organochlorine compounds released during different processing stages. Therefore, some cost-effective and nonpolluting practices such as enzymatic treatments are required for the potential mitigation of effluents released in the environment. Various xylanolytic enzymes such as xylanases, laccases, cellulases and hemicellulases are used to hydrolyse raw materials in the paper manufacturing industry. These enzymes are used either individually or in combination, which has the efficient potential to be considered for bio-deinking and bio-bleaching components. They are highly dynamic, renewable, and high in specificity for enhancing paper quality. The xylanase act on the xylan and cellulases act on the cellulose fibers, and thus increase the bleaching efficacy of paper. Similarly, hemicellulase enzyme like endo-xylanases, arabinofuranosidase and β-D-xylosidases have been described as functional properties towards the biodegradation of biomass. In contrast, laccase enzymes act as multi-copper oxidoreductases, bleaching the paper by the oxidation and reduction process. Laccases possess low redox potential compared to other enzymes, which need some redox mediators to catalyze. The enzymatic process can be affected by various factors such as pH, temperature, metal ions, incubation periods, etc. These factors can either increase or decrease the efficiency of the enzymes. This review draws attention to the xylanolytic enzyme-based advanced technologies for pulp bleaching in the paper industry., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Paper-based analytical devices have prominently emerged as a group of diagnostic tools with prospective to eliminate the expensive, time-consuming, and intricate analytical methodologies. Wax printing has been a dominant technique to fabricate hydrophobic patterns on paper for fluid control, but the discontinuation of commercial solid ink printers has begun a genesis of alternate wax patterning strategies. In this study, a simple and rapid fabrication methodology for realizing a 96-well microtiter plate on paper has been developed. The method involves the use of commercially available polystyrene microplates as a stamp for wax patterning. The technique further eradicates the requirement of customized stamps and the step of heating paper substrates for creating wax barriers. Thus, wax stamped paper microplates can be used for a wide range of bioanalytical tests maneuvering reduced generation of non-biodegradable waste, minimal reagent usage, and inexpensive readout strategies. The viability of the fabricated platform has been assessed by colorimetric detection of glutathione using 3,3',5,5'-tetramethylbenzidine-H 2 O 2 redox system. RGB analysis of the colorimetric response showed a linear concentration range from 0 to 90 µM ( R 2  = 0.989) along with a detection limit of 28.375 µM., Supplementary Information: The online version contains supplementary material available at 10.1007/s10404-022-02606-3., Competing Interests: Conflict of interestThe authors declare that they have no known competing interests that could have appeared to influence the work reported in this paper., (© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

The potential of alkaline cellulo-xylanolytic enzymes from non-pathogenic Bacillus subtilis strain was tested for deinking of photocopier waste paper. Cellulase and xylanase play a crucial role in deinking of different types of waste paper. Partial purification of cellulo-xylanolytic enzymes was carried out using ultrafiltration followed by ammonium sulfate precipitation. The ultrafiltered enzyme was used for deinking the photocopier waste paper along with chemical deinking. An enzyme dose of 0.6 IU/g and reaction time of 60 min for ultrafiltered cellulo-xylanolytic enzyme significantly increased deinking efficiency, tear index (9.52%) and folding endurance (5±2%) as compared to chemical deinking. There was improvement in strength properties such as tear index and double-fold along with freeness of pulp (18%). There was slight decrease in tensile index (0.6%) and burst index (16%) while ISO brightness remained unaffected. Enzymatic deinking (74.3%) by ultrafiltered cellulo-xylanolytic from Bacillus subtilis was found significant over conventional chemical deinking., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Concerns about human health regarding the large use of bisphenol A in thermal papers have led to its replacement by bisphenol S. Analyses of bisphenols require several sample pretreatment steps, which are laborious, expensive, and time-consuming. A paper spray ionization mass spectrometry (PSI-MS) was developed to detect and quantify bisphenol S in three different brands of thermal papers commercially available. Parameters such as paper size, and paper position relative to the mass spectrometer inlet were evaluated. The analyses were performed in selected ion monitoring mode on a linear ion trap mass spectrometer. The developed method presented absolute recovery values ranging from 92.2 to 109.04%, accuracy values from -1.2 to 9.0%, and inter assay precision from 1.8 to 5.6% and enabled LOD as low as 5 ng g -1 . The concentration of bisphenol S in all of the three brands of BPA-free thermal papers evaluated ranged from 1.36 to 6.77 μg g -1 , and the concentrarion of BPA ranged from 6.56 to 16.4 μg g -1 in all samples of thermal paper evaluated. The PSI-MS method described here was comparable to the conventional ones, such as liquid chromatography coupled with mass spectrometry and gas chromatography coupled with mass spectrometry described in the literature. The present study proved to be practical, fast, and efficient for the direct determination of bisphenol S in thermal papers. Furthermore, the methodology here described showed to be a promising alternative to replace the classical methods for determination of bisphenol S, due to its simplicity, and no needing of any sample pretreatment., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Bio-bleaching effect on bagasse pulp using xylano-pectinolytic enzymes produced by a bacterial species was studied in order to evaluate the potential of these enzymes in paper industry. In this study, action of enzymes was maximum with xylanase/pectinase dose 7/1.75 IU/g, pulp consistency 1:12.5 g/L, pH 8.5, temperature 50° C and 180 min of treatment time. Under the optimized bio-bleaching conditions, removal of reducing sugars (6.15±0.05 mg/L), brightness (16.08%), whiteness (25.54%) and release of chromophores (hydrophobic and phenolic compounds and lignin impurities) were maximum, along with decrease in kappa number (26.28%), and yellowness (27.88%) values were obtained. Improvement in the various physical properties like breaking length (10.28%), burst index (29.55%), tear index (5.02%), double fold (14.89%), Gurley porosity (15%) and viscosity (8.6%), along with the reduction of chlorine dioxide dose by 27%, was also observed. There is also reduction in COD and BOD values of bio-bleached effluents by 27.62% and 20.52%, respectively. This is the first report on bio-bleaching of bagasse pulp using xylano-pectinolytic enzymes., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In this study, a microfluidic paper-based analytical device (μPAD) was integrated with a smartphone app capable of offline (without internet access) image processing and analysis for the rapid colorimetric detection of glucose. A self-inking stamp was used to form hydrophobic channels on a piece of paper-towel due to its superior water absorption efficiency. As demonstrated, the developed sensor was employed for the colorimetric detection of glucose in artificial saliva in the linear scope of 0 - 1 mM with a calculated detection limit of 29.65 μM. The experimental results show that the quantitative analysis of glucose with the proposed smartphone platform could be completed in less than one minute. The app developed for the smartphone platform is capable of extracting the color-changing area with an embedded image processing tool which could address the problem of color uniformity in the detection zones of μPAD. The integrated platform has great potential to be used for non-invasive measurements of glucose in body fluids, like tears, sweat and saliva.

The objective of this study was to check the potential of crude xylano-pectinolytic enzymes in bleaching of rice straw pulp, in order to reduce the toxic waste load for managing the environmental pollution. The xylano-pectinolytic enzymatic bleaching step for delignification was found to be most effective at pulp consistency 1:10 g/ml, xylanase:pectinase dose of 9:4 IU/ml, pH 8.5 and treatment time 180 min at temperature of 55 °C, and resulted in lowering of kappa number of the rice straw pulp by 15.29%. In subsequent bleaching stages, this enzymatic pre-bleaching treatment also resulted in 30% reduction of active chlorine dioxide dose without any loss of optical properties. Significant improvement in various physical properties of the enzymes treated pulp, tear index (15.43%), breaking length (11.11%), double fold number (25.92%), burst index (9.88%) and viscosity (13.63%), and Gurley porosity (39.86%) was also noticed. This approach resulted in reduction of BOD and COD values by 21.07% and 26.57%, respectively. This is the first study on the use of crude xylano-pectinolytic enzymes for bio-bleaching of rice straw pulp.

In this work, a new chemiluminescence (CL) system of Co-Fe prussian blue analogs nanocubes (Co-Fe PBA NCs) that can catalyze luminol to produce strong CL in the absence of H 2 O 2 was established. Co-Fe PBA NCs have the property of oxidase-like activity, and it can catalyze the generation of active oxygen radicals in a dissolved oxygen system. Since caffeic acid (CA) can remove reactive oxygen species in the system, a sensitive detection method for CA on a paper-based chip was developed. Under the optimal conditions, this method showed a good linear response to CA in the range of 10 - 800 ng mL -1 with a limit of 3 ng mL -1 . The proposed method had been used for the determination of CA in tea samples. The results may open a new avenue for the catalytic property on luminol CL system without extra oxidants.

We report on a simple, cost-effective, instrument-free, and portable distance-based paper device coupled with NFs for the determination of glucose. The analysis reaction is based upon the oxidative etching reaction of silver nanoparticles (AgNPs) in the presence of H 2 O 2 that is produced from glucose after a glucose oxidase (GOx) catalytic reaction leading to a morphological transformation of AgNPs. A color band length of AgNPs is coated on to a detection channel and then etched by H 2 O 2 , and these were changed from a purple color to colorless as a correlate of the glucose concentration. To improve the performance of the enzyme immobilization, NFs, which are biocompatible without compromising their structure and biological activity, were then placed onto the sample zone. The naked-eye detection limit was 0.1 mM for 40 min of analysis time. The recoveries of glucose spiked in the artificial urine samples and control urine samples were then verified by our device and were in the acceptable range of 96 - 100%.

In this study, action of ultrafiltered xylano-pectinolytic enzymes from a bacterial strain has been evaluated for bleaching of rice straw soda-anthraquinone pulp. Maximum bio-bleaching effect and release of non-cellulosic impurities were noticed with xylano:pectinolytic enzymes dose of 6.0:2.1-IU/g pulp, treatment time of 180 min at 10% pulp consistency, pH 8.5, and temperature 55 °C. Microscopic images of bio-bleached rice straw pulp also confirmed the efficacy of ultrafiltered enzymes, as bleaching agent. This bio-bleaching treatment resulted in 15.38% and 32% reduction in kappa number and active chlorine dioxide dose, respectively, along with increase in various physical properties, burst index (12.50%), tear index (19.07%), breaking length (14.30%), double fold number (26.31%), Gurley porosity (45.32%) and viscosity (16.17%). This bio-bleaching approach not only improved the pulp quality but also reduced environmental pollution load by decreasing effluent parameters values of BOD and COD by 23.67% and 27.44%, respectively. This study indicates that use of ultrafiltered xylano-pectinolytic synergism for rice straw pulp bleaching will ultimately help in making the process eco-friendly, along with better quality pulp. This is the first report on use of ultrafiltered xylanase and pectinase, produced from a bacterial isolate, for bleaching of rice straw pulp.

The pulp bleaching process removes or transforms the chromophore groups in the pulp, so that the final product reaches a desired brightness. However, this chemical treatment inevitably results in yield loss. Therefore, the objective of this work was to quantify the yield loss caused during the bleaching of kraft pulp of Pinus radiata delignified with oxygen. The material was submitted to three distinct ECF sequences (D 0 (EPO)D 1 D 2 , D 0 (EPO)D 1 P, and Z/EDP). At the end of each bleaching stage, the pulp brightness and the loss of gravimetric yield of the process were determined, and the generated filtrates were collected. From these filtrates, the pollutant load of the effluent was determined by measuring the content of total dissolved solids, the chemical oxygen demand, the concentration of total organic carbon carbon, and the adsorbable organic halogens. Among the whole sequences, the Z/EDP sequence had the lowest gravimetric yield, the highest pollutant load in the collected filtrate, and lowest potential for adsorbable organic halogens generation. There was good correlation between the loss of yield from the bleaching process and the organic load of the generated effluent; and among the techniques studied, the quantification of total organic carbon was the most appropriate method for the indirect quantification of the yield loss during the bleaching process of the studied material.

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

This research was carried out with an objective to examine the efficacy of ultrafiltered xylano-pectinolytic enzymes in pulping of sugarcane bagasse. Maximum biopulping was achieved with enzyme dose of xylanase (175 IU / g bagasse) and pectinase (75 IU / g bagasse) at treatment period of 180 min. The temperature, pH, and bagasse to liquid ratio for biopulping experiments were kept constant at 55 o C, 8.5, and 1:10 (g/ml), respectively. The ultrafiltered biopulping improved chemical pulping, resulted in 25.11%, 9.17% increase in brightness, unscreened pulp production and 11.81, 59.50, and 49.14% decrease in total solids, rejections. and kappa number, respectively. The bagasse biopulping also resulted in 15% decrease of alkali load to attain similar kappa number and optical properties as obtained under 100% alkali dosage. Ultrafiltered biopulped-unbleached samples showed significant increase in breaking length (13.55%), burst index (40.21%), tear index (19.04%), double fold (42.5%), Gurley porosity (28.21%) and viscosity (13.37%) in comparison with non-enzymatically treated control pulp samples. In comparison with non biotreated-bleached pulp samples, ultrafiltered biopulped-bleached samples also resulted in higher burst index (56.80%), breaking length (17.38%), double fold (39.58%), tear index (3.38%), viscosity (30.68%), and Gurley porosity (52.50%). This environmentally sustainable ultrafiltered biopulping approach for sugarcane bagasse has the potential to decrease the demand of chemicals, ultimately pollution along with enhance the quality of paper.

Bisphenol A (BPA) is a high production volume chemical that has wide industrial applications, especially as a color developer in thermal papers. The present study focused on the determination of levels of BPA in thermal receipts collected from different locations in Akure, Nigeria, and the estimation of daily intake of BPA through dermal absorption. Thermal receipts were collected from different locations, and the levels of extracted BPA were determined using fluorescence spectroscopy. The daily intake of BPA was estimated, and the amount was compared with the reference value. BPA was detected in all the samples analyzed with levels ranging from 1.50 to 3.16 mg/g. These values were lower than the values detected in thermal receipts obtained from other countries. The estimated mean daily intakes of BPA by dermal absorption due to handling of thermal receipts were 0.20 and 9.89 μg/day for the general population and the occupationally exposed individuals, respectively, and were much lower than the reference value of 50 μg/kg bw/day provided by the European Food Safety Authority. This indicates that dermal exposure to BPA is not a serious health risk to the population.

Lipase enzyme has a critical role in deinking process along with other lignocellulosic enzymes. In this paper, we try to demonstrate the role of lipase in the enzyme cocktail used for enzymatic deinking. For this, we identified a potential lipolytic bacterium, Pseudomonas mendocina ED9 isolated from elephant dung with a molecular weight of 35 kDa. During the Box-Benhken model optimization, a maximum lipase activity of 105.12 U/g, which was 12.36-fold higher than the initial enzyme activity and 1.3-fold higher than the activity obtained during the Plackett Burman design, was achieved. A maximum lipase activity of 105.12 U/g was obtained after optimization. Ammonium sulphate (60%) precipitation resulted in a specific activity of 68.19 U/mg with a 1.4-fold purification and yield of 64%. Lipase from P. mendocina ED9 exhibited a Km of 0.5306 mM and Vmax of 25.0237 μmol/min/mg. A Δ brightness of approximately 14.5% were achieved during the enzymatic deinking using cocktail comprised of cellulase, xylanase and lipase. This reports the significant role and efficacy of lipase in enzyme cocktails for deinking applications. This formulation will reduce the pollution and environmental toxicity of conventional chemical deinking.

In this study, suitability of xylano-pectinolytic enzymes in pulping of wheat straw has been explored. The suitable biopulping conditions were optimized, with xylanase dose of 400 and pectinase dose of 120 IU/g wheat straw, 1:10 (g/ml) material to liquid ratio, 55 °C temperature, 3 h treatment time, 0.75% Tween 80 and pH 8.5. Enzymatic pretreatment efficiently increased the pulpability of wheat straw, generated pulp with higher yield, lower kappa number (15.67%) and rejections (59.65%) in comparison with chemical pulp. The brightness of pretreated wheat straw pulp with enzyme was 16.04% higher than that of the non-enzyme treated wheat straw pulp. The biopulping resulted in 12% reduction of pulping chemicals along with more residual alkali content, in order to achieve similar optical and chemical properties as obtained by 100% chemically treated pulp. Physical properties of pulp also improved after enzymatic pretreatment, increasing burst index (26.50%), tear index (18.22%) and breaking length (5.56%). The enzyme plus chemical (88% pulping chemicals) treated pulp showed improvement in brightness and whiteness, with reduction in yellowness at all bleaching stages. In comparison with chemically bleached pulp, biopulp with reduced alkali dose (88%) had higher breaking length (6.63%), double fold number (51.28%), tear index (2.83%), burst index (24.31%), along with increased viscosity (6.12%) and Gurley porosity (27.50%). These results clearly suggest that biopulping of wheat straw with xylano-pectinolytic enzymes can reduce chemical loading during soda-anthraquinone pulping and also improve the quality of paper. This is the first report demonstrating the biopulping of wheat straw using crude xylano-pectinolytic enzymes.

Estazolam (EST) is a common sedative-hypnotic drug with a risk of abuse. Therefore, rapid on-site detection of EST is necessary to control the abuse of EST. In this paper, a fast, simple, and sensitive method is demonstrated for the detection of EST in both water and beverages, using surface-enhanced Raman spectroscopy (SERS) techniques. Au@Ag core-shell nanoparticles (NPs) assembled on the filter paper as a SERS substrate exhibit good applicability and practicality. At the same time, density functional theory (DFT) is used to assign the vibration mode of the EST molecules, which can be used as a guide for subsequent experiments. The lowest detectable concentration of EST in aqueous solution can be as low as 5 mg/L, and signal uniformity is excellent (RSD 687 = 5.56%, RSD 1000 = 4.35%). In addition, EST components artificially added to orange juice and pomegranate juice can be effectively detected by simple pretreatment with a minimum detection concentration as low as 10 mg/L. Therefore, this study found that the use of Au@Ag core-shell nanoparticles paper-based SERS substrate provides a quick and easy method for the detection of illegally added drugs in beverages.

Loop-mediated isothermal amplification or LAMP has been identified to be an efficient technology for point-of-care diagnostics. Paper-based LAMP technique has tremendous potential in replacing the existing tube-based technology as the manufacturing cost of a paper-based device is comparatively lower and easy-to-use. LAMP-based paper diagnostic device for Mycobacterium tuberculosis (MTB) detection is of extreme importance as it will help in early and rapid diagnosis of the affected patients. The fabrication of these devices requires assessment of design parameters on the extent of LAMP amplification reaction. Hence, CFD studies would be extremely beneficial from the design perspective. The current work presents an insight into the CFD simulations for LAMP amplification reaction on a porous paper membrane (nitrocellulose membrane). The convection-diffusion-reaction model is solved on a COMSOL Multiphysics 5.0 platform. Studies on effect of pore size, aspect ratio and initial DNA concentration on the extent of DNA amplification reaction have been carried out. The current paper-based technique is effective in detecting a minimum of 5 copies of DNA contrasting the previous semi-quantitative technique which demonstrated the detection of minimum 98 copies. Overall, the simulation results displayed almost 96% enhancement in the DNA amplification rate on paper membrane. Graphical abstract Graphical abstract for the computational study of DNA amplification reaction via LAMP technique on a porous paper membrane.

Six elemental chlorine-free bleaching sequences were studied to see their effect on quality of pulp produced and quantity of pollutants generated during bleaching of wheat straw soda pulp. Impact of parameters like adsorbable organic halogens (AOX), chemical oxygen demand (COD), biochemical oxygen demand (BOD) and sodium adsorption ratio, pH and total dissolved solids generated during bleaching on environment as index of global pollution (I GP ) was also studied. The purpose of the study was to investigate six elemental chlorine-free bleaching sequences to compare the pulp quality, effluent properties and their impact on environment. An oxygen delignification stage before D 0 E OP D bleaching sequence reduced the AOX, COD, colour and BOD by 44%, 42%, 36% and 33%, respectively, whereas an ozonation stage before bleaching reduced the same by 70%, 66%, 73% and 60%, respectively, as compared to those of control. The generation of pollutants as AOX, COD, colour and BOD was reduced further by 88%, 80%, 90% and 77%, respectively, with the use of short bleaching sequences (DD, DP and PD) as compared to those of control. The environmental impact as I GP with D 0 E OP D bleaching sequence was 2.65 which got reduced to 1.44 with bleaching sequence OZPD. Bleaching sequence OZD 0 E OP D was found the most effective for improving brightness and whiteness of the pulp, whereas short bleaching sequence OZPD found the most effective for reducing generation of pollutants during bleaching among different bleaching sequences studied. Graphical abstract.

The objective of this study was to evaluate the bleaching effect of light sources with various wavelengths using 30% hydrogen peroxide (HP) in vitro. The hematoporphyrin-stained paper was bleached with HP and irradiated for 10 min using LED light sources with 265, 310, 365, 405, or 450 nm respectively. In control group, HP was applied for 10 min without light irradiation. The bleaching procedure was repeated two times. The L*a*b* values of the samples before bleaching and after each bleaching step were measured using a colorimeter. Color changes of specimens were then calculated and statistically analyzed. There was an interaction between light sources and time of irradiation in the color change (p < 0.05). Time and light sources significantly affected ΔE and ΔL (p < 0.05). The light source of 256 nm showed the highest bleaching effect over time followed by that of 310 nm, which were statistically different from other groups (p < 0.001). The 365 nm, 450 nm groups, and control group showed low bleaching effect visually with no significant differences in ΔE and ΔL (p > 0.05). It was concluded that the wavelengths of the light sources affected the bleaching by HP. The 310-nm light can be a potential source for bleaching.

This paper describes the design and development of miniaturized microfluidic paper-based analytical devices (μPADs) for biological assays and enzyme storage instruments. Here, a glucose assay utilizing glucose oxidase (GOx), horseradish peroxidase (HRP), and potassium iodide (KI) is used as the model system. The efficacy of the miniaturized devices is further examined by assessing the activity of acetylcholinesterase (AChE). Two types of μPADs were developed: one, "strip" chips of detection zones of area 0.5, 0.1 cm 2 and, two, "grid" chips of detection zone 0.05 cm 2 . The devices are easily fabricated via a wax printing process whereby lines of wax are deposited onto chromatographic paper and heated to create rows of hydrophobic barriers. The "strip" chips were subjected to three different temperature environments (-20, 0, and 20°C) over 30 days and glucose assays conducted at intermittent times yielding a correlation between corrected average inverse yellow intensity, days, and glucose concentration. Calculated and experimentally derived color intensity values for 1, 4, and 9 mM glucose concentrations after a 7-day storage study showed a good correlation (0.89 - 15.76% error). Both types of μPADs are effective platforms as potential point-of-care (POC) diagnostic devices and display minimal enzyme denaturation. μPADs of this size show promise as alternative devices for resource-limited regions and especially those areas where materials and instrumentation are not always available.

Porous magnesium oxide (MgO) films on carbon fiber paper (CF) have been successfully fabricated in a hydrothermal route at different calcination temperatures. The CF@MgO samples (CF@MgO-300, -400, and -500) show different morphologies with the increasing surface area from 3 for CF to 27 m 2  g -1 for CF@MgO-400. Among the four investigated samples, the CF@MgO-400 exhibits the highest phosphate removal ability (~ 1230 mg g -1 ) with promising applications for the large-scale utilization at low cost.

Paper mill wastewater leads to a serious damage on the environment owing to the high content of organic matters, suspended solids, toxic substances, and lignin. Hence, exploring new treatment technologies is the passion of environmental engineers to minimize the effluent impact on the environment and cleaner production aspects. This research focused on the performance of full-scale coagulation-fluctuation/DAF system for pre-treatment of high strength wastepaper-recycling wastewater and its effect on biodegradability improvement. To optimize unit performance, optimum coagulant and flocculant doses were firstly determined by jar test without prior change and adjustment of pH in lab-scale experiments. The optimum dosages were obtained by 1500 mg L -1 polyaluminum chloride (PACl) as coagulant coupled with 40 mg L -1 cationic polyacrylamide (C-PAM) as flocculant. Percentage removals of 39 ± 10, 6.8 ± 3.6, 31.0 ± 6.7, 24.0 ± 3.8, and 33.0 ± 20.0 were achieved for COD, sCOD, BOD 5 , sBOD 5 , and color, respectively. The average BOD 5 to COD ratio after pre-treatment increased from 0.44 to 0.5, whereas the ratio of sBOD 5 /sCOD dropped from 0.65 to 0.53. A superior effectiveness in reduction of TSS (98.1%) and VSS (98.4%) was also achieved. The results show that the application process is able to prevent malfunction operation in the following bioreactors which is obtainable through bio-treatability enhancement of pre-treated wastewater and reducing the risks of clogging and sludge washout. Attached growth processes are suggested to be applied in the further anaerobic/aerobic processes because of high proportion of soluble fraction of COD in the effluent to avoid poor floc formation and dispersed growth problems.

Peat-based growing media are not ecologically sustainable and peat extraction threatens sensitive peatland ecosystem. In this study, olive-stone waste (OSW) and paper waste (PW) were used in different ratios-as growing media-for ornamental crop production, as peat (P) substitutes. Marigold (Calendula officinalis L.), petunia (Petunia x hybrita L.) and matthiola (Matthiola incana L.) plants were grown in (1) P (100%), (2) P:OSW (90%:10%), (3) P:OSW (70%:30%), and (4) P:OSW:PW (60%:20%:20%). The physicochemical properties of these substrates and the effects on plant growth were determined. The addition of 10-30% OSW into the substrate increased marigold height compared to plants grown in 100% peat. No differences in plant size, plant biomass (leaves and flowers), and dry matter content were found. Adding PW, in combination with OSW, maintained marigold height and total number of flowers produced to similar levels as in plants grown in 100% peat. In matthiola, adding 30% OSW into the substrate reduced plant size and fresh weight, but not plant height. No differences were observed when plants grew in lower OSW (i.e., 10%) content. Petunia's height, its total number of flowers and flower earliness (flower opening) were increased in the presence of OSW compared to the plants grown in 100% peat. The addition of OSW did not affect petunia's size and fresh weight among treatments. The addition of PW suppressed several plant growth-related parameters for both matthiola and petunia. The insertion of OSW did not change leaf chlorophyll content whereas the presence of PW decreased chlorophylls for marigold, petunia, and matthiola. Both OSW and PW altered the content of total phenolics and antioxidant capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) in leaves and flowers for marigold and petunia. Both 30% OSW and PW increased antioxidative enzyme metabolism due to the increased damage index and lipid peroxidation observed in plants. Leaf N and P content decreased in PW-based media, while matthiola displayed visual phytotoxicity symptoms when PW was added into the substrate. The present work indicates that up to 30% of OSW can replace peat for marigold and petunia growing and only up to 10% of OSW for matthiola, while the addition of PW on top of OSW is not recommended, so further research is needed.

This study aimed to maximise the amount of CO 2 storage by indirect carbonation using paper sludge ash (PSA), which is an alkaline industrial waste. The properties of the following three types of solvents were considered: acids (acetic acid and hydrochloric acid), ammonium salts (ammonium chloride and ammonium acetate) and others (sodium citrate and water). When carbon dioxide was injected into calcium leachates prepared from PSA using acids, carbonation did not occur, and using ammonium salts as solvent, the carbonation efficiency was low. However, after pH swing of the leachates using sodium hydroxide and ammonia solution for acid and ammonium salt solvents, up to 324 kg CO 2 /(ton PSA) and 175 kg CO 2 /(ton PSA) were stored, respectively. When carbon dioxide was injected into calcium leachates prepared from PSA using sodium citrate or water, solid was initially generated which later dissolved. In order to solve this problem, CO 2 injection was stopped just before the pH of the solution reached 10.5 for sodium citrate and 8.3 for water, resulting in the storage of 136 kg CO 2 /(ton PSA) and 29 kg CO 2 /(ton PSA), respectively. Solids obtained through carbonation were pure calcium carbonate.