Waste Paper Research Articles

Waste newspaper as cellulose resource of activated carbon by sodium salts for methylene blue and congo red removal

The work was aimed at evaluating the adsorptive properties of waste newspaper (WN) activated carbons chemically produced using sodium salts for methylene blue (MB) and congo red (CR) removal. The activated carbons, designated as AC1, AC2, AC3 and AC4 were prepared through impregnation with NaH2PO4, Na2CO3, NaCl and NaOH, respectively and activation at 500 °C for 1 h. The activated carbons were characterized for surface chemistry, thermal stability, specific area, morphology and composition. The AC1 with a surface area of 917 m2/g exhibits a greater MB capacity of 651 mg/g. Meanwhile, a greater CR capacity was recorded by AC2 at 299 mg/g. The pseudo-second order model fitted well with the kinetic data, while the equilibrium data could be described by Langmuir model. The thermodynamic parameters, i.e.., positive ΔH°, negative ΔG° and positive ΔS° suggest that the adsorption of dyes is endothermic, spontaneous and feasible at high solution temperature. To conclude, WN is a potential cellulose source for producing activated carbon, while NaH2PO4 activation could be employed to convert WN into activated carbon for effective dye wastewater treatment.

Improving urban waste management: A comprehensive study on household waste generation and spatial patterns in the Grand Guayaquil Metropolitan Area.

This study tackles the growing global concern about municipal waste management, particularly in cities like the Grand Guayaquil Metropolitan Area (GGA). Through realistic field studies on in situ household waste generation and geographic information system (GIS) tools, this work offers a framework to predict the quantities and types of recyclable household waste for any metropolitan area in Latin America. Over 4 weeks, students collected, sorted and weighed recyclable waste types, including plastic, paper, metal, glass and fabric, from 776 sampled household of the GGA. ArcGIS survey tool identified household locations and allowed to survey different socio-demographic features. With the help of ArcGIS interpolation method, the total household waste generation for GGA was predicted, and the classification of the different types of recyclable waste was also spatially distributed for the study area. The report identified notable trends in plastic waste, specifically polyethylene terephthalate waste's steady prevalence and 42% growth rate, emphasizing the importance of enhanced recycling techniques. Spatial density maps showed a heterogeneous waste distribution across the GGA, emphasizing locations with higher waste output. This study demonstrates that improving recyclable waste collection can be accomplished with a moderately cheap expenditure by collaborating with academia to overcome knowledge gaps. This strategy provides opportunities to mitigate the environmental impacts of poor waste management.

Advancing reinforcement of sustainable gypsum composites: High-performance design by reusing waste materials

This study tends to optimize and develop an innovative gypsum material by incorporating hybrid waste compounds. Using a Doehlert design, this work explores the effects of introducing paper (X1), polystyrene (X2), and polyester fibers (X3), as well as their interactions, on gypsum's thermophysical and mechanical behavior. Bulk density, thermal conductivity, flexural strength, compressive strength, and the fire resistance test were performed on the developed formulations. Statistical analysis emphasizes the significant influence of all process variables on gypsum properties. Polyester fibers notably enhance flexural strength when combined with the cooperative effect of paper and polystyrene wastes, which strike a balance between physical and mechanical characteristics. The optimum formulation parameters lead to a significant 33% decrease in bulk density, a 43% reduction in thermal conductivity, a notable 42% increase in flexural strength, and a significant reduction in compressive strength of around 50%, but still meet the 2 MPa standard. The new samples show ductile behavior, highlighting gypsum's potential as a load-bearing material with excellent thermal insulation properties and impressive fire resistance. This research significantly improves our understanding of the effectiveness of a gypsum compound incorporating waste in a hybrid manner, bringing this approach into line with sustainable development objectives.

Synergistic effect of cellulo-xylanolytic and laccase enzyme consortia for improved deinking of waste papers

This study reports the cellulo-xylanolytic cocktail production from Hypocrea lixii GGRK4 using multi-objective genetic algorithm-artificial neural network tool, resulting in 8.32 ± 1.07 IU/mL, 51.53 ± 3.78 IU/mL activity of CMCase and xylanase, respectively with more than 85 % residual activity at 60 °C and pH 6.0. Interestingly, metal ions viz. K+ and Ca2+ stimulated the enzyme activity, whereas Fe2+ and Cu2+ reduced the activity. Significant amounts of hydrophobic compounds, chromophores, and phenolics were released after wastepapers deinking. The deinking efficiency of 73.60 ± 2.45 % and 38.60 ± 1.34 % was obtained for photocopier paper and newspaper, respectively, whereas brightness of 89.90 ± 2.10 % ISO and 44.90 ± 1.63 % ISO was reported for both types of waste papers. The physical strength of deinked photocopier paper and newspapers, i.e., tensile index (3.10 and 0.50 %), tearing index (7.10 and 4.83 %), and burst factor (8.61) were enhanced whereas double fold property was decreased proving wastepaper reusability. This consortium showed effective and significant enzymatic deinking efficiency for recycled wastepapers.

Controlled Interlayer Binding and Healing Improve the Transverse Properties of Upcycled Disposable Waste Wood.

Recovery and reuse of bulk waste wood are particularly challenging because of usage defects and contaminations. Here, we present a robust and efficient strategy for regenerating used wood veneers into high-performance structural materials through micro/nano interface manipulation. Our approach involves using cellulose-based interlayers to bind together two waste wood plates without an external adhesive by partially dissolving and regenerating the interlayer using a solution of ionic liquids and dimethyl sulfoxide. The mechanical properties of the regenerated wood exceed that of natural wood, displaying over a 16 and 20 times increase in transverse tensile strength and modulus, respectively, and 4-6 times improvement in longitudinal tensile strength and modulus. Nanoscale mechanical analyses show that the improvement is possible as a result of several factors, including the robust network structure of the interlayer, the good adhesion at the wood-interlayer interface, the compacted wood structure, and the low stiffness and deformation gradients between the interlayer and the wood structure. The interlayers can be created from waste papers and wood particles by taking advantage of the nanofibrillar structure of cellulose.

Stable loading of MOF-derived carbon skeleton encapsulated Ni and BiOBr on carbonized cellulose fibers for fabricating high-performance and recyclable photocatalytic paper

The highly dispersed small-size metal co-catalysts can effectively improve the photocatalytic efficiency of semiconductor photocatalysts by separating photogenerated electrons and enriching active sites. However, this system tends to aggregate in the absence of carrier, resulting in the decrease of active sites. Here, MOF-derived carbon skeleton (MDCS) encapsulated Ni nanoparticles (Ni@MDCS) and BiOBr was loaded onto carbonized cellulose fibers (CCF) with the help of polydopamine (PDA) to construct high-performance and recyclable photocatalytic paper for photocatalytic degradation of organic dyes in water. The characterization results showed that MDCS promoted good dispersion of Ni nanoparticles and provided sufficient active sites. And Ni@MDCS as a co-catalyst accelerated the separation of photogenerated carriers in BiOBr. The PDA improved the loading state of Ni@MDCS on CCF and converted into N-doped C in the carbonization process for further increasing the transfer efficiency of photogenerated electrons. In the composite paper, the stable loading of Ni@MDCS/BiOBr hybrid on CCF improved the dispersion and reusability of photocatalyst. The degradation rate of rhodamine B on CCF/PDA-C/Ni@MDCS/BiOBr paper was as high as 94.6 % after 60 min visible light irradiation, which was about 2.5 times higher than that of CCF/BiOBr paper. During 10 cycles, CCF/PDA-C/Ni@MDCS/BiOBr paper maintained high photocatalytic efficiency and good structural stability. This study provides a new way for developing high-performance and recyclable photocatalytic paper.

Suspect screening of per-and polyfluoroalkyl substances in paper by selective and non-selective extraction with UHPLC-Q orbitrap MS

Non-targeted analysis and suspect screening of per- and polyfluoroalkyl substances (PFAS) in various matrices have gained traction with advancements in accurate mass analytical instruments. This study employed ultra-high performance liquid chromatography coupled to quadrupole orbitrap high-resolution mass spectrometry for PFAS suspect screening of paper grades used in the paper recycling chain. The samples were prepared using two extraction techniques; selective accelerated solvent extraction with weak anionic exchange solid-phase extraction and non-selective ultrasonic-assisted extraction. A suspect screening protocol was established to tentatively identify suspected PFAS against spectral databases using a systematic approach of peak filtering and study-specific thresholds for reporting, linked to a confidence level. The possible prevalence of previously unreported PFAS in several paper materials across the various collection sites in the paper recycling chain was inferred by the common detection of short-chain polyfluoroalkyl ketones and diketones in the paper recycling chain. The suspect screening tentatively identified 41 unique PFAS, with 3 common to both pre-treatment techniques. The detection of unique PFAS by the two sample pre-treatment techniques highlighted the significance of both selective and non-selective extraction in PFAS screening endeavours. Further, it showed the importance of understanding the acquisition mechanisms employed in mass spectrometry where data-dependent acquisition triggered fragmentation in certain identified compounds, and not in others. The tentatively identified PFAS indicated that there were several previously unreported PFAS in the paper recycling chain and that additional studies were required to investigate their abundance, possible persistence, bioaccumulation and toxicity, in relation to their functional groups and carbon chains.

Multi-Colored Aqueous Ink for Rewritable Paper.

As sustainable and eco-friendly replacements to conventional paper, rewritable paper is a very attractive alternative for communication, information circulation, and storage. Development is made for rewritable paper using chromogenic materials that change its color in presence of external stimuli. However, the new techniques have faced several major challenges including feasible operational method, eco-friendly approach. Herein, a simple, convenient, and eco-friendly strategy is described for the preparation of rewritable paper substrate, and multi colored ink for efficient use in writing, painting or printing purpose. In addition, writing with "invisible ink" on the rewritable paper can be realized for potential anti-counterfeiting application. The written, painted, or printed information on the paper substrate can be easily erased using an aqueous solution. Thus, the original paper can be retrieved and the paper substrate can be reused multiple times. Besides, the written or printed information can be retained for a prolonged time at ambient conditions. Overall, this approach shows the rewritable paper as a prototype of multicolor writing/painting application, offering a sustainable solution for reducing paper waste and promoting environmental stewardship.

Reconsidering banning the imports of waste paper: The implications for the environmental, economic and health impacts

Waste paper (WP) has become indispensable raw materials for paper industry. China has banned all imported WP since 2021, this one-size-fits-all policy has caused wide debates due to lack of a multiple and systematic assessment. Herein, a three-dimensional comprehensive assessment of environment, economy and health risk was established to compare non-deinking paper (NP) and deinking paper (DP) with imported/domestic waste paper (IWP/DWP). Assessment indicated that IWP was strongly recommended for NP with 20.96 %, 17.39 % and 20.92 % lower than DWP in environment, economy and health risk, respectively. Although the health risk of IWP was 58.14 % higher than that of DWP, it did not exceed the threshold, IWP was still recommended for DP with 19.14 % and 4.18 % lower than DWP in environment and economy. Toxicity-related impact categories predominated at midpoint level, especially human carcinogenic toxicity (50.97–59.12 %), which was largely caused by the emission of large quantities of toxic pollutants from the key processes (e.g., electricity generation (25.14–38.28 %) and wood pulp (31.99 %)), especially chromium (VI) (51.08–60.21 %). While human health (93.89–95.1 %) dominated all endpoint impact categories, which was mainly attributed to the top substances (i.e., CO2) from electricity generation (28.47–42.78 %). Importantly, actual cost might be markedly underestimated without considering environmental cost, the ecosystems damage was the primary source of external cost, and the internal cost was concentrated in raw materials (47.57–61.67 %). The health risk of contaminants in WP was closely associated with their manufacturing process and raw materials. The major health risk resulted from heavy metals, particularly for As and Cr. In conclusion, banning all IWP should be deliberated carefully, high-quality IWP should be imported to decrease environmental and economic burdens via enhancing supervision, performing import subsidies and tax incentives, and administrative approvals (facilitating industry consolidation and merging small and medium-sized enterprises).

Recycled newspaper cellulose based colorimetric sensor of biogenic amines for food spoilage indication

Cellulose was extracted from newspaper waste and purified by alkali treatment process. The white color cellulose without ink and glue was obtained and then characterized by Fourier transform infrared spectroscopy and X-ray diffraction spectroscopy. Thermogravimetric analysis reported that the purified cellulose was thermally stable at the room temperature. The microstructure of cellulose showed random orientation of fiber with air-instituted in between, confirmed by scanning electron microscopy and laser confocal microscopy. The purified cellulose was applied as the substrate for enzymatic colorimetric sensor. The sensor was fabricated by immobilizing pH indicator and diamine oxidase on the cellulose surface. Then, the sensor responses toward the bogenic amines (cadaverine, putrescine and histamine), the food spoilage indicator, were measured by naked eye and spectrophotometry. The color change from orangish to a blueish color with linear range of 0.25–2.0 mg/mL for cadaverine, 0.05–2.0 mg/mL for putrescine, and 2.5–10.0 mg/mL for histamine, were obtained. This platform was advantageous due to ease of use, low cost, portable size, and user-friendly readout. Ultimately, this recycled newspaper based colorimetric biogenic amine sensor was applied for the detection of biogenic amines in ground pork samples with satisfactory results.

Biotite and ZnO embedded carbon aerogel composite for enhanced photocatalytic activity to degrade ciprofloxacin under sunlight stimulation

This study was explored the photocatalytic efficiency of biotite and ZnO embedded carbon aerogel (CA) photocatalyst to degrade ciprofloxacin (CIP) antibiotic from an aqueous medium by sunlight harvesting. CA came from waste newspaper through pyrolysis technique. Biotite was extracted from Bramapurta River's sand through high-tension magnetic separation techniques. The developed catalyst was characterized by applying FESEM, EDS, XRD, and XPS. The bandgap (1.69 eV) of the catalyst was determined from Tauc's plot. The photocatalytic study showed that, optimum degradation was achieved at 98.471 %, 84.576 %, 77.997 % and 59.607 % for 2, 5, 10 and 20 mg/L CIP containing solution respectively in 180 min at its natural pH applying only employing 0.25 g/L dosage. Moreover, in the pH study, catalyst showed maximum degradation 88.773 % for 5 mg/L CIP containing solution at pH 7 exposing the same irradiation time and dosage. The degradation followed pseudo-first-order kinetics with a maximum rate constant of 0.01831 min−1 which attributes to the first degradation of CIP through ROS. The scavenger test suggested that •OH− and e− played a vital role in the photodegradation process. Regeneration studies confirmed that photocatalysts showed better degradation efficiency until five cycles. Fusion of metal oxides in the catalyst might play a vital role in the multiple photodegradation cycles without losing stability of the composite. FESEM, EDS, and XPS characterization of the spent catalyst was performed for understanding its morphological and chemical change. An antimicrobial study was performed to confirm its efficiency against of gram-negative bacteria (E. coli) and gram-positive bacteria (S. aureus), which suggested that the catalyst is very effective in destroying gram-negative bacteria compared to gram-positive bacteria.

Mass flow and microbial shifts in recirculated two-phase anaerobic digestion for biohythane production: Effect of hydraulic retention time

Biohythane, the promising gaseous biofuel, can be produced by the recirculated two-phase anaerobic digestion (R-TPAD). The effect of hydraulic retention time (HRT) as 30, 20 and 10 days on biohythane production via R-TPAD (recirculation ratio = 0.4) was investigated with co-digestion of food waste and paper waste. The results showed that HRTs of 30 and 20 days maintained stable performance for R-TPAD but HRT of 10 days led to the final decrease in biogas production. The failure in the end was attributed to the wash-out of microbes. The removal efficiencies for COD and carbohydrates were decreased by short HRTs while for VS it remained relatively stable at about 75.7 ± 4.0%. All through the operation, acidogenic phase and methanogenic phase were separated stably and butyrate pathway was the dominant pathway for hydrogen fermentation in the first stage. The microbial community in the first stage reached the highest diversity when total HRT was 20 days, where the hydrogen production rate was the highest. The genera Lactobacillus and Caproiciproducens kept dominating the dark fermentation in the acidogenic phase, and Ruminococcus and Methanosarcina were decreasing in the methanogenic phase. The biohythane yields were 411 mL/g-VSfed, 332 mL/g-VSfed and 253 mL/g-VSfed, respectively, where the H2 contents were 18.4%, 14.7% and 8.8%, respectively.

Development of Magnetic Immobilized Cellulase Biocatalysts for Saccharification of Paper Waste

Development of Magnetic Immobilized Cellulase Biocatalysts for Saccharification of Paper Waste

Development of STEM-Based Biology Laboratory Activities in Creating Filter Paper Utilizing Indigenous Materials

This study aims to develop STEM-based laboratory activities in creating filter paper using indigenous materials. The researcher initially devised a formulation for creating filter papers from indigenous materials (Corchorus olitorius leaves and waste papers) and subjected them to various tests. It was determined that Filter Paper B is the most effective among all other formulations. Subsequently, it was compared to Grade 2 Whatman filter paper using the same methodology. These precise procedures were also incorporated into the laboratory activities developed by the researcher and utilized by students during implementation. Following the tests stated in the laboratory manual, the students also determined that filter paper B containing 20 g (40%) of jute mallow leaves and 30 g (60%) of waste paper was the most effective in terms of the criteria and qualities. A pre-and post-test were also administered during the implementation. This is aimed at assessing the degree of STEM literacy among students regarding the topic of Filtration. It is interesting to note that using STEM - Based Biology Laboratory Activities increased the students’ STEM literacy. Hence, it is recommended that the STEM – Based Biology Laboratory Activities be used in class to foster scientific learning among students.

An MRS-YOLO Model for High-Precision Waste Detection and Classification.

With the advancement in living standards, there has been a significant surge in the quantity and diversity of household waste. To safeguard the environment and optimize resource utilization, there is an urgent demand for effective and cost-efficient intelligent waste classification methodologies. This study presents MRS-YOLO (Multi-Resolution Strategy-YOLO), a waste detection and classification model. The paper introduces the SlideLoss_IOU technique for detecting small objects, integrates RepViT of the Transformer mechanism, and devises a novel feature extraction strategy by amalgamating multi-dimensional and dynamic convolution mechanisms. These enhancements not only elevate the detection accuracy and speed but also bolster the robustness of the current YOLO model. Validation conducted on a dataset comprising 12,072 samples across 10 categories, including recyclable metal and paper, reveals a 3.6% enhancement in mAP50% accuracy compared to YOLOv8, coupled with a 15.09% reduction in volume. Furthermore, the model demonstrates improved accuracy in detecting small targets and exhibits comprehensive detection capabilities across diverse scenarios. For transparency and to facilitate further research, the source code and related datasets used in this study have been made publicly available at GitHub.

Characteristics and degradability of laser print waste paper fiber reinforced PLA resin matrix composite materials

AbstractAs is well known, Laser print paper is usually produced with high‐quality chemical wood pulp. The laser print waste paper fiber (LPWF) is a high‐quality secondary fiber, and the research and development of high‐value utilization technology for laser print waste paper has attracted much attention in the field of renewable resource recycling. In this study, LPWF was used to reinforce poly(lactic acid) (PLA) composites in the field, and the composites were modified with bioenzyme, cationic polyacrylamide (CPAM), and nano‐silicon carbide (Nano‐SiC) to enhance the interfacial compatibility of LPWF/PLA composites. The study systematically investigated the effects of various modification methods on the characteristics and degradability of composites made from laser print waste paper fiber reinforced PLA resin matrix. The results showed that the mechanical properties of the composites treated with CPAM and Nano‐SiC were significantly improved, with tensile strengths of 54.3 and 59.5 MPa, and flexural strengths of 85.1 and 91.5 MPa, respectively, and the water absorption of the composites was reduced after the modification treatment, while the thermal stability was improved. The degradation performance of the composites in various water environments indicated that the inclusion of LPWF accelerated the water degradation rate of the composites, with the maximum degradation rate of the composite reaching 1.26% in 30 days.Highlights Laser print waste paper is an excellent quality recyclable fiber resource. Four modifiers were used to modify LPWF/PLA composites. Characteristics and degradability of the composites were investigated. Significantly improved properties of CPAM and Nano‐SiC modified composites. The degradation rate of composites is increased by the addition of LPWF.

Simple Synthesis of Cellulose Triacetate from HVS Paper Waste and Its Application for Optode

The optode membrane is a membrane that can identify ions in an aqueous solution. One of the most widely used optode membranes is cellulose triacetate based. Cellulose triacetate (CTA) has the characteristics of hydrophobic, transparent, elastic, and affordable. There are sources of cellulose triacetate that can be utilized and waste paper is one of them. Waste paper is extracted to obtain the cellulose, then by acetylization reaction to produce cellulose triacetate. The resultant cellulose triacetate has a degree of substitution (DS) of 2.89 and an acetyl group percentage (% AG) of 43.64. The standard and synthesized CTA optode membrane are tested for performance with various parameters, ie optimum pH, optimum immersion time, working range, limit of detection (LOD), and limit of quantification (LOQ). The standard CTA optode membranes and synthesized worked at pH 3 and 4 with optimum immersion time for 15 min, respectively. The optode produced a linear response in detecting Cr(VI) ion in the concentration range of 0.02-1 mg/L for standard CTA with an R2 of 0.9726 and 1-25 mg/L for synthesized CTA with an R2 of 0.9764, The limit of detection (LOD) and limit of quantitation (LOQ) were 0.0015 mg/L and 0.0051 mg/L for standard CTA, while 0.0224 mg/L and 0.0749 mg/L for synthesis CTA respectively. Since both optode membranes' performance test results are adequate, the synthesis results of CTA optode membranes can be employed as one source of cellulose triacetate.

Analysis of Waste Utilization of Refuse Derived Fuel (RDF) Into Briquettes for Steam Power Electric Generation

Waste in Indonesia reaches 65.2 million tons/year, dominated by organic and inorganic waste. Around 36% of the total waste has not been managed properly, including 4K1P waste (paper, wood, cloth, rubber, and plastic), which is flammable and can be made into RDF briquettes using the pyrolysis method and paraffin adhesive which will used three variations of raw materials, namely from organic, inorganic and mixed waste. The quality of the three briquettes was compared based on calorific value, ash content, water content, and PLTU fuel requirements if used as fuel for a 7.5 MW capacity PLTU. The weight of the initial raw material for briquettes is 2 kg which produces 875 grams of paper carbon charcoal, 648 grams of wood, 1.09 kg of plastic, 856 grams of cloth, and 1.16 kg of rubber, resulting in 10 pieces of organic, inorganic and mixed briquettes each. The test results show that inorganic briquettes have the best quality with a calorific value of 8,075.92 cal/g, water content of 1.75%, and ash content of 10.84%, where the calorific value and water content meet SNI-01-6235-2000. The minimum fuel requirement for a PLTU using RDF briquettes is inorganic briquettes, namely 3.05 tonnes/hour with an annual requirement of 26,205.6 tonnes/year. It can be concluded that inorganic briquettes have the best quality and require the least amount of fuel to be used in PLTU.

Forecasting the waste production hierarchical time series with correlation structure

AbstractContinuous increase in society’s prosperity causes overwhelming growth of the produced municipal solid waste. Circular economy initiatives help to solve this problem by creating closed production cycles, where the produced waste is recycled, or its energy is recovered. An embedment of such principles requires implementation of new waste management strategies. However, these novel strategies must be based on the accurate forecasts of future waste flows. Municipal solid waste production data demonstrate behavior of hierarchical time series. Among all possible approaches to hierarchical times series forecasting, this article is focused on the reconciliation of the base waste generation forecasts. The novel method, that is based on the game-theoretically optimal reconciliation of hierarchical time series, is presented. The modified approach enables to incorporate interdependencies between time series using correlation matrix and to obtain the forecasts corresponding to the unique solution of the optimization problem. The potential of the proposed abstract approach is demonstrated on the waste production data of paper, plastics (both primarily sorted by households), and mixed municipal solid waste from the Czech Republic.

Compressive Strength of Geopolymer Mortar Reinforced with Rice Husk Fibers

Geopolymer concrete has been proposed to minimize carbon dioxide emissions related to the cement production industry. This environmentally friendly material consists of industry waste materials activated chemically by an activation solution. In this study, the geopolymer mortar has been designed with 70% fly ash and 30% metakaolin. Hydroxide sodium in 14 molar concentrations blended with sodium silicate in a 2.5:1 ratio was used as the activation solution. Rice husk fibers were added as reinforcement in (1%, 1.5%, and 2%), and waste paper (paper pulp and paper ash) was added in (1%, 2%, and 5%) by volume of cementitious material. The geopolymer mortar samples underwent a curing process through exposure to a temperature of 60°C in an oven for 24 hours. The findings indicate that the samples reinforced with 2% rice husk fibers exhibited the most significant improvement in compressive strength, with 59% and 55% increases after 7 and 28 days of curing, respectively. In general, using waste paper and rice husk fibers significantly enhanced the compressive strength of geopolymer mortar.