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The presence of pharmaceuticals in water is a major problem worldwide. To alleviate this, this study produced carbon blends from avocado seeds and paper waste and activated them with hydrogen peroxide (H2O2), nitric acid (HNO3) and potassium permanganate (KMnO4). The effectiveness of the adsorbents was tested in removing ibuprofen (IBU) and paracetamol (PRC) from water. Characterization of the adsorbents by SEM, BET, FTIR and TGA revealed that the morphology was porous, with a large surface area and several functional groups bound to the surface. The concentration effect experiments showed that the uptake of IBU and PRC increased with an increasing initial concentration and that these data were consistent with the Freundlich model. The contact time effect showed that the uptake of PRC was rapid in the initial phase for all the adsorbents. However, the rate gradually slowed down and equilibrium was reached after 40 min for BCMN, 60 min for BCMH and BCMP and 120 min for BCM. IBU, on the other hand, showed that equilibrium was reached after 30 min for BCMN, BCMH and BCMP and after 120 min for BCM. These data complemented the PSOM. The model is based on chemisorption, where electrons are transferred and shared, and hydrogen bonding and π-π interactions. The △Ho value confirms that the sorption of IBU and PRC was endothermic. The △So was positive, indicating greater freedom at the solution interface during uptake.

Non-wood paper production, such as bamboo paper, is an alternative to meet the massive demand for paper consumption in the recent era. Bamboo paper, made from Bambusa vulgaris fibers and manufactured with the addition of activated nano-carbon, shows an improvement in paper quality. However, there is a potential worry with the incorporation of activated carbon since it may hinder the degradation process of paper. Concerning the substance's life cycle, degradation assisted by the fungal decomposer of this new product is crucial. This study investigated the effects of the white-rot fungi, viz. Phlebiopsis sp and Pycnoporus sp., on the degradation of bamboo paper with- or without- activated nano-carbon (BPAC and BPNAC). In vitro experiments that combined two variables (Fungal agents and Paper types) were carried out for 12 weeks. The results revealed that Pycnoporus sp. was more effective in decomposing both BPAC and BPNAC rather than Phlebiopsis sp. After being degraded by Phlebiopsis sp. and Pycnoporus sp. for 12 weeks, the remaining mass of BPAC was 64.14% and 48.96%, respectively, while the BPNAC was 69.89% and 38.25%, respectively. The ability of these fungal agents on composite-paper degradation was compared to other similar studies. Further investigation and possible applications were discussed.

As a kind of biomass resource, waste office paper can be used as a carbon precursor to prepare carbon materials. In this work, carbon microspheres with regular shape, uniform particle size and high carbon content were successfully prepared from waste office paper via a hydrothermal synthesis method with sulfuric acid as the catalyst. The effects of reaction temperature and sulfuric acid dosage on the morphology of the carbon microspheres were studied. The formation mechanism of the carbon microspheres was investigated by analyzing the structure and composition of the products. The results show that the hydrolysis of cellulose in waste paper under hydrothermal conditions was the key for the formation of carbon microspheres. The temperature of hydrothermal reaction and the use of sulfuric acid can affect the morphology of carbon microspheres. The carbon microspheres synthesized at 210 °C with 10 mL sulfuric acid have the best surface morphology, with uniform particle size and higher dispersion. Cyclic voltammetry and electrochemical impedance spectroscopy show that the carbon microspheres have good capacitance performance and can be used in capacitors. This study provides a low-cost precursor for carbon microspheres as well as a new method for the recycle of waste paper. [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium metal is deemed a promising anode material for the next-generation batteries with high specific energy. Unfortunately, the growth of Li dendrites and infinite volume change during cycling, caused by the "hostless" feature of metallic Li, have posed a great challenge to the commercialization of Li metal anode. The introduction of appropriate host materials for Li metal is highly desirable. In this work, a N, P dual-doped 3D carbon derived from low-cost quantitative filter paper (NPCQP) is designed and fabricated for direct using as a host for Li metal anode. The resulting NPCQP host achieves a high deposition/stripping Coulombic efficiency of above 97.5 % with a low nucleation overpotential. Moreover, the NPCQP@Li symmetric cells enable an excellent long-term cycling performance (1000 h) with an ultralow voltage hysteresis (12 mV) and stable interface behavior. When paired with the commercial LiFePO 4 cathode, the full cell with NPCQP@Li anode displays impressive long-term cyclic stability and rate capability, outperforming the counter cell with bare Li anode. This contribution sheds light on the rational design of viable host for practical lithium metal anodes. [ABSTRACT FROM AUTHOR]

Copyright of Indonesian Journal of Forestry Research is the property of Indonesian Journal of Forestry Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Carbon microsphere was successfully synthesized from waste office paper via hydrothermal method and high temperature treatment in nitrogen atmosphere. The process of carbon microsphere synthesis from waste office paper fiber using concentrated sulfuric acid was studied, and the influence of H2SO4 concentration and reaction time on the hydrolysis reaction was considered. To investigate the mechanism of conversion of waste office paper to carbon microsphere, Fourier transform infrared spectrometry was used to analyze the chemical composition of the supernatant liquid product and the non-carbonized carbon microsphere. The weight loss of the non-carbonized carbon microsphere was assessed through thermogravimetry. Scanning electron microscopy was used to analyze the morphology. The hydrolysis reaction of waste office paper fiber and synthesis mechanism of carbon microsphere under different conditions were evaluated. The results showed that when the reaction time reached 24 h, the product had uniform particle size and was well dispersed, and the more sulfuric acid present led to the waste office paper fiber being more thoroughly hydrolyzed. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A carbonized interlayer effectively helps to improve the electrochemical performance of lithium–sulfur (Li–S) batteries. In this study, a simple and inexpensive carbon intermediate layer was fabricated using a traditional Korean paper called "hanji". This carbon interlayer has a fibrous porous structure, with a specific surface area of 91.82 m2 g−1 and a BJH adsorption average pore diameter of 26.63 nm. The prepared carbon interlayer was utilized as an intermediary layer in Li–S batteries to decrease the charge-transfer resistance and capture dissolved lithium polysulfides. The porous fiber-shaped carbon interlayer suppressed the migration of polysulfides produced during the electrochemical process. The carbon interlayer facilitates the adsorption of soluble lithium polysulfides, allowing for their re-utilization in subsequent cycles. Additionally, the carbon interlayer significantly reduces the polarization of the cell. This simple strategy results in a significant improvement in cycle performance. Consequently, the discharge capacity at 0.5 C after 150 cycles was confirmed to have improved by more than twofold, reaching 230 mAh g−1 for cells without the interlayer and 583 mAh g−1 for cells with the interlayer. This study demonstrates a simple method for improving the capacity of Li–S batteries by integrating a functional carbon interlayer. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, carbon quantum dots (CQDs) and rhodamine B (RhB) were physically mixed to construct a highly selective and sensitive ratiometric fluorescent sensor (CQDs@RhB) for the quantitative and visual detection of Hg2+. After adding Hg2+, the emission peak of CQDs at 445 nm was quenched and the peak of RhB at 575 nm remained unchanged; the ratio of the two emission peaks had a linear relationship with the Hg2+ concentration. The CQDs@RhB had a detection range of 0–15 µM and the limit of detection (LOD) is 65.93 nM and a color change from blue to pink was visible to the naked eye under ultraviolet light. The study revealed a static quenching mechanism of CQDs@RhB. The established method was successfully applied to the detection of Hg2+ in real water and rice samples with satisfactory results. In addition, a portable fluorescent paper-based sensor platform was developed using computer software assistance. The relationship with Hg2+ concentration was constructed by converting the pictures obtained under ultraviolet light to RGB color mode for visualization and quantitative detection of Hg2+. This study provides a valuable strategy for constructing a rapid detection system for Hg2+ in the field. [ABSTRACT FROM AUTHOR]

Due to large sulfur (S) content and simple manufacturing techniques, free‐standing cathodes for lithium‐sulfur (Li−S) batteries are gaining a lot of attention recently. Waste office paper, which is consumed in large quantities annually, was used to make a free‐standing paper‐based carbon (FPC) substrate, which inherited fiber‐like morphology. In addition, reduced graphene oxide (rGO) nanosheets modified FPC (rGO@FPC) host was also prepared by a vacuum filtration method. After S impregnation, the FPC/S and rGO@FPC/S free‐standing cathodes were employed in Li−S batteries. The rGO@FPC/S free‐standing cathode exhibited extremely competitive electrochemical performance, including a reversible discharge capacity of 315 mAh g−1 at 0.5 C after 500 cycles. This is due to the uniform S distribution, which boosts the utilization ratio, and the significant blocking action for polysulfide ions, which prevents the redox shuttle effect. [ABSTRACT FROM AUTHOR]

The present study examines the assumptions, modeling structure, and results of DICE-2023, the revised Dynamic Integrated Model of Climate and the Economy (DICE), updated to 2023. The revision contains major changes in the treatment of risk, the carbon and climate modules, the treatment of nonindustrial greenhouse gases, discount rates, as well as updates on all the major components. Noteworthy changes are a significant reduction in the target for the optimal (cost-beneficial) temperature path, a lower cost of reaching the 2 °C target, an analysis of the impact of the Paris Accord, and a major increase in the estimated social cost of carbon. [ABSTRACT FROM AUTHOR]

The carbon oxides (CO2 and CO) in the insulating oil of power transformers come from the thermal aging of cellulosic insulating paper; the CO2/CO ratio can reflect the aging state of cellulosic insulating paper. At present, the formation mechanisms of CO2 and CO in oil-immersed power transformers are still unclear. In this article, the ReaxFF reaction force field is used to simulate the thermal aging process of cellulosic insulating paper, and the main reaction pathways of CO2 and CO molecules formed by cellulose pyrolysis are obtained. The study finds that the amount of CO2 and CO generated is related to temperature. When the pyrolysis temperature continues to rise, the amount of CO2 generated shows a downward trend, while the amount of CO generated continues to increase, and the CO2/CO ratio continues to decrease. The simulation results are consistent with the previous experimental results. Through pathway tracking, it is found that the CO2 and CO molecules are mainly derived from certain specific atoms of cellulose molecules. The COSMO-RS module is used to analyze the change trend of the solubility of CO2 and CO in insulating oil with temperature. The results show that the solubility of CO2 and CO decreases with the increase of insulating oil temperature, which provides theoretical support for accurate application of carbon oxides aging evaluation index at different temperatures. [ABSTRACT FROM AUTHOR]

In this study, carbon quantum dots (CQDs) and rhodamine B (RhB) were physically mixed to construct a highly selective and sensitive ratiometric fluorescent sensor (CQDs@RhB) for the quantitative and visual detection of Hg2+. After adding Hg2+, the emission peak of CQDs at 445 nm was quenched and the peak of RhB at 575 nm remained unchanged; the ratio of the two emission peaks had a linear relationship with the Hg2+ concentration. The CQDs@RhB had a detection range of 0–15 µM and the limit of detection (LOD) is 65.93 nM and a color change from blue to pink was visible to the naked eye under ultraviolet light. The study revealed a static quenching mechanism of CQDs@RhB. The established method was successfully applied to the detection of Hg2+ in real water and rice samples with satisfactory results. In addition, a portable fluorescent paper-based sensor platform was developed using computer software assistance. The relationship with Hg2+ concentration was constructed by converting the pictures obtained under ultraviolet light to RGB color mode for visualization and quantitative detection of Hg2+. This study provides a valuable strategy for constructing a rapid detection system for Hg2+ in the field. [ABSTRACT FROM AUTHOR]

In this study, the performance of a paper-based, screen-printed biofuel cell with mesoporous MgO-templated carbon (MgOC) electrodes was improved in two steps. First, a small amount of carboxymethyl cellulose (CMC) was added to the MgOC ink. Next, the cathode was modified with bilirubin prior to immobilizing the bilirubin oxidase (BOD). The CMC increased the accessibility of the mesopores of the MgOC, and subsequently, the performance of both the bioanode and biocathode. CMC also likely increased the stability of the electrodes. The pre-modification with bilirubin improved the orientation of the BOD, which facilitated direct electron transfer. With these two steps, an open circuit potential of 0.65 V, a maximal current density of 1.94 mA cm−2, and a maximal power density of 465 μW cm−2 was achieved with lactate oxidase as bioanode enzyme and lactate as fuel. This is one of the highest reported performances for a biofuel cell. [ABSTRACT FROM AUTHOR]

Scheme 1 The illustration of the synthesis of dual-emission type N, Cl-doped carbon dots by a simple hydrothermal route and the implications. [Display omitted] • Dual-emission N, Cl-CDs with strong orange fluorescence were simply synthesized. • The N, Cl-CDs exhibited precise sensing toward VB 2 , VB 9 , VB 12 in aqueous solution. • Visually semiquantitative detection of three VBs were performed on test strip. • The detection of VBs were successfully applied in real samples. Although a few of fluorescent probes based on carbon dots (CDs) for vitamin B (VB) determination have been emerged, none of them can realize the detection of different kinds of VB. In this paper, nitrogen, chlorine co-doped dual-emission CDs (N, Cl-CDs) with emissions at 404 nm and 595 nm have been easily synthesized. VB 2 , VB 9 and VB 12 can all induce obvious fluorescence turn-off response toward the N, Cl-CDs. Based on that, three types of VBs are quantitatively and sensitively evaluated in aqueous solution with wide concentration ranges of 14.9–135.0 μM, 34.7–89.8 μM and 29.8–79.8 μM, respectively. Importantly, visual semiquantitative detection of VBs on a test strip are also proposed. Moreover, the current N, Cl-CDs have been successfully applied to the detection of VBs in real samples. The N, Cl-CDs are sensitively multifunctional sensors for three kinds of VBs in aqueous solution and the visual semiquantitative detection by test paper assay is simple, portable and inexpensive. [ABSTRACT FROM AUTHOR]

The effect of bipolar and driving electrodes materials and also the electrolyte conductivity on the required potential for the beginning of the water electrolysis in the paper-based closed cell bipolar electrochemistry is investigated. The importance of the electrode material is studied by placement of various carbon paste mixtures as an electrode on the paper. Carbon paste mixtures are prepared with different carbon allotropes and various binders such as paraffin and ionic liquids. The effect of hydrophobicity, conductivity, and presence of common additives such as gold nanoparticle is discussed in detail. The role of electrolyte conductivity on the needed ∆E for water electrolysis initialization is investigated. It has been proved that even in the absence of ionic current in the closed bipolar setups, electrolyte conductivity can be effective. [ABSTRACT FROM AUTHOR]

SiFeO(N,C)‐based ceramic papers were prepared via a one‐pot synthesis approach by dip‐coating a cellulose‐based paper template with a polymeric perhydropolysilazane precursor modified with iron(III)acetylacetonate. The preceramic composites were subsequently pyrolyzed in ammonia atmosphere at 500, 700, and 1000°C, respectively, and the characteristics of the three resulting ceramic papers were comparatively investigated. Scanning electron microscopy revealed that in each sample, the morphology of the template is successfully transferred on the ceramic system, with the cellulose‐derived fibers being converted to elemental carbon encased by a SiFeO(N,C) coating. Electron transparent cross‐sectional samples for transmission electron microscopy (TEM) were prepared from the ceramic papers, employing a standard ultramicrotomy slice cutting procedure, allowing for a detailed characterization of their in situ generated micro‐/nanostructure as well as occurring crystalline phases. TEM imaging and diffraction revealed that depending on pyrolysis temperature a different microstructure with a distinct phase assemblage is generated in the polymer‐derived ceramic papers. Crystallization from the polymer precursor starts with the precipitation of wüstite (Fe(1‐x)O) nanoparticles at 700°C inside the ceramic coating and secondary ε‐FexN at the fiber‐coating interface. Upon pyrolysis at 1000°C however, the sample primarily accommodates metallic α‐iron nanocrystals that impart ferromagnetic characteristics to the ceramic paper. The results show that the template‐assisted polymer‐derived ceramic route is a feasible approach in the production of complex ceramic compounds with fibrous paper‐like morphology. By adjusting the pyrolysis temperature, microstructure and phase composition of the ceramic paper can be conveniently tailored to the needs of its respective application. [ABSTRACT FROM AUTHOR]

Carbon containing waste has a certain calorific value and utilization value due to the presence of carbon elements. However, the current treatment methods are mostly traditional landfill disposal, incineration, or expensive physical and chemical reaction methods, which clearly do not comply with the rules of the current clean and resource-saving society. In this paper, a new technology and system for carbon containing wastes is proposed, which comprehensively treats and recycles carbon containing wastes, including solid waste, wastewater, waste gas, etc., using pyrolysis–gasification two-stage-cycle technology. The calculation results indicate that the technical scheme proposed in this article is feasible and can achieve the recycling of intermediate and final products, the efficient and clean utilization of carbon containing waste, and the graded utilization of energy. The clean utilization rate of carbon containing waste can be effectively improved, the energy consumption and cost of separate treatments can be reduced, and zero waste emissions can be completely achieved by the comprehensive pyrolysis–gasification two-stage-cycle treatment and resource utilization technology, which is one of the preferred solutions for future resource-saving societies. [ABSTRACT FROM AUTHOR]

The security of food and drink water is of great concern in our daily life, because the threat from heavy metals pollution in environment is extensively existed. Carbon dots (CDs) is promising for a wide range of applications because of its excellent chemical and optical properties. Herein, yellow emissive carbon dots (YCDs) were constructed by a facile mild condition. The YCDs emitted bright emission at 562 nm with excitation of 420 nm and the quantum yield of 17.44%. The fluorescence of YCDs can be utilized of sensing Hg2+ with limit of 16.8 nM. The mechanism of detection for Hg2+ can be attributed to static quenching effect (SQE) and dynamic quenching effect (DQE) process. A fluorescent portable paper detection platform based on YCDs integrated with a smartphone APP were developed for real-time and rapid analysis of Hg2+ with limit of 0.11 μM. Notably, YCDs were successfully employed to the detection of Hg2+ in various food and real water with recoveries of 97.50 ± 2.63% – 108.64 ± 0.15%, indicated satisfied sensing performance and excellent environmental tolerance. The fluorescence sensing system based on YCDs provided a reference for the construction of portable sensors for hazardous substance monitoring. [Display omitted] • Controllable synthesis of yellow emissive carbon dots by mild heating process. • A visual testing platform based on paper sensor was developed for Hg2+ on-site assay. • High selectivity and sensitivity with rapid response achieved by smartphone APP. • Real sample analysis for Hg2+ detection with satisfied results. [ABSTRACT FROM AUTHOR]

A well-designed support material between catalyst and substrate can always significantly enhance the performance of an electrode on water oxidation. In this work, a functional Ni and N-doped carbon layer (NNC) was designed on carbon paper (CP) via pyrolysis by using a controlled electrodeposited polyporphyrin as a precursor. Consequently, the fabricated NiFe-LDH/NNC/CP achieved a catalytic current density of 100 mA cm−2 at a small overpotential of 231 mV with a low Tafel slope of 26.0 mV dec−1, as well as high durability for more than 360 h. The insights are that N-doping reinforces the hydrophilicity and the catalyst binding capacity, while Ni-doping intensifies the conductivity. [ABSTRACT FROM AUTHOR]

Herein, a simple method to prepare porous carbon that inhibits hydrogen evolution is used, which has enormous advantages for both capacitors and lead‐acid batteries. The quantitative filter paper spongy porous carbon (SQFPC) is successfully synthesized by the two‐step method. SQFPC displays a porous, spongy structure with a large specific surface area (1847 m2 g−1). In electrochemical tests, SQFPC exhibits high specific capacitance (244 F g−1 at 1 A g−1) and a capacitance retention rate of 72.5% at 40 A g−1. In addition, the capacity of the battery with 0.5 wt% SQFPC is improved by 57.6% at a discharge rate of 0.1C, and the cycle life under the high‐rate partial state of charge is 9.3 times that of the blank battery. The enhanced battery performance is related to the unique structure and surface functional groups of carbon, which speed up ion movement inside the battery and provide active sites for lead deposition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Filter paper is used as carbon source to prepare highly porous N-doped carbon. • KHCO 3 is chosen as the activator because it is safe and non-corrosive. • Addition of urea at the activation step significantly improves the surface area. • At 0 °C and 20 bar, the carbon shows high CO 2 uptake of 19.65 mmol/g. Herein, we presented the preparation of N-doped porous carbon from lab used filter paper. Filter paper was first carbonized at 500 °C. The obtained carbon was then pyrolyzed with KHCO 3 and urea. Effects of KHCO 3 activation on the carbons' physicochemical properties were thoroughly investigated. The derived carbon materials were also tested for CO 2 adsorption with pressure up to 20 bar. The carbons exhibited very high CO 2 uptake of 19.65 mmol/g at 0 °C and 20 bar. The correlations between adsorption performances and the carbons' physicochemical properties at 1/20 bar were analyzed and discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A CFMs-based RFP was proposed for ultrasensitive sensing of AO. • Dual-emissive CFMs were prepared by loading CDs into MF microspheres. • A smartphone-integrated paper device were prepared for AO visualization. A paper-based assay for visualization of auramine O (AO) was for the first time established by using CFMs as a ratiometric fluorescent probe (RFP). The CFMs were melamine formaldehyde microspheres (MFMs) incorporated with carbon dots (CDs), where the CDs species as sensing units and MFMs as a signal amplification carrier. The proposed RFP can quantitatively measure AO content from 0.0 to 10.0 μM and exhibited an ultralow limit of detection (LOD, 15.7 nM). In particular, obvious luminescence color change of CFMs from blue to green was perceived with naked-eyes and therefore, a solution-based and a paper-based visualization platform were respectively proposed for on-site visual detection of AO with LODs of 1.15 μM and 0.83 μM, separately. Finally, those fluorescence methods were adopted in sensitively quantitative measurement of AO within various food and drug samples, providing new prospects for analysts and technical support in food quality monitoring. [ABSTRACT FROM AUTHOR]

Rapid screening of bacteria by low-cost and eco-friendly material-based approaches is still a major challenge. Herein, a colorimetric biosensor was designed for the ultrasensitive and rapid detection of Gram-positive bacteria. The biosensor exploited polydopamine and polyethyleneimine (PDA-PEI)-modified papers for separating bacteria and carbon dots (CDs) for selective colorimetric detection of Gram-positive bacteria. Noble metal-free CDs can target Gram-positive bacteria by binding with peptidoglycan and possess peroxidase-like activity. Thus, they can avert the step of modifying recognition probes, facilitating biosensor fabrication, and reducing the cost. This biosensor can detect S. aureus as low as 1 cfu mL−1, L. monocytogenes as low as 5 cfu mL−1, and B. subtilis as low as 9 cfu mL−1 within 55 min. In addition, a portable device was constructed to enable convenient and on-site quantitative detection of Gram-positive bacteria. The feasibility of the biosensor was verified by detecting Gram-positive bacteria in eggshell and sausage samples with recoveries ranging from 91.2% to 110%. [Display omitted] • A colorimetric biosensor was developed based on PDA-PEI@paper and CDs. • The biosensor can selectively detect Gram-positive bacteria. • PDA-PEI@paper can enrich bacteria to improve sensitivity. • CDs with peroxidase-like activity can target Gram-positive bacteria. • The LODs of the biosensor for Gram-positive bacteria were less than 10 cfu mL−1. [ABSTRACT FROM AUTHOR]

One challenge in capitalizing on the affordability, sustainability, and accessibility of biohybrid solar energy conversion, including devices based on Photosystem I (PSI), is the identification of metal‐free electrode materials to replace the inorganic substrates commonly found in solar cell development. Herein, commercially available Toray carbon paper (CP) is investigated as a high surface area, carbon electrode for the development of photoactive bioelectrodes consisting of PSI and poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Mediated anodic photocurrent is achieved at both PSI multilayer and PSI–polymer composite films on CP electrodes subjected to flame pretreatment. Film preparation is optimized by utilizing potential sweep voltammetry in place of potentiostatic conditions for polymerization. The optimized PSI–PEDOT:PSS films achieve a threefold increase in polymer growth under potential sweep conditions, quantified through net charge consumed during electropolymerization, resulting in a fourfold increase in photocurrent density (−53 vs −196 nA cm−2). The ability to prepare photoactive PSI‐polymer films on metal‐free CP electrodes opens the door to a rapidly scalable system for biohybrid energy production ultimately leading to more affordable, sustainable, and accessible energy. [ABSTRACT FROM AUTHOR]

Biomass-derived carbon materials have been widely studied as oxygen reduction reaction (ORR) catalysts in recent years, and most directly carbonized materials are still inferior to commercial 20% Pt/C in ORR performance. By ball-milling the carbon powder carbonized by yuba, the interior of carbon particles was exposed, which showed that N content inside carbon particles is higher than that on the surface. Then ultrasonication was employed to refresh the surface of the as-obtained carbon particles to increase C-N-active sites to improve their ORR performance. As a result, the as-treated carbon material was comparable to 20% Pt/C as ORR catalyst in all the key ORR activity parameters (only 7 mV and 16 mV negative shift on onset and half-wave potential, respectively, and 0.28 mA cm−2 at −0.5 V versus Hg/HgO larger in limiting current density). Moreover, the ORR durability and the CO resistance of YUC-850 outperformed that of 20% Pt/C. The detailed experiments indicate that ultrasonication treatment can efficiently exfoliate the small raised material portions of low N content from regular particles to expose more refreshed surface with high N content to improve ORR activity. The subsequent centrifugation collection can remove the small particles to inhibit active site coverage and particle coarsening in service, which leads to further improvement in ORR activity and durability. Ultrasonication of another biomass-derived carbon material also showed significantly improved ORR performance. In conclusion, the application of ultrasonication treatment to biomass-derived carbon materials is proposed to fully promote their ORR activity and durability. The superior ORR performance of the treated carbon materials in this paper also indicates that biomass-derived carbon materials indeed have the potential to serve as redox catalysts in the future. [ABSTRACT FROM AUTHOR]

With companies increasingly expected to undertake potentially costly climate-response strategies, we explore the roles of management control systems (MCSs) in how companies simultaneously manage their decarbonization objectives and their financial commitments. Based on research at 19 European chemical, steel, and utility corporations, we extend the concept of "proactive/reactive" response strategies by proposing three additional decarbonization strategies: wholesale green transition, green segmentation, and engagement. Second, we highlight the recursive relationship between MCSs and these strategies. We also postulate a dynamic model of MCSs evolution in the decarbonization context, whereby engagement strategies form the foundation of green segmentation and vice versa. Third, drawing on an integrative model, we propose three antecedents to companies' response strategies relevant in this context, namely, their framing of decarbonization as an opportunity or a threat, the different perspectives on the availability of green technologies, and the different perspectives on the policy context. [ABSTRACT FROM AUTHOR]

Co-doped carbon nanofiber mats can be prepared by the addition of cobalt acetate to the polyacrylonitrile/DMF electrospun solution. Wastewater obtained from food industries was utilized as the anolyte as well as microorganisms as the source in single-chamber batch mode microbial fuel cells. The results indicated that the single Co-free carbon nanofiber mat was not a good anode in the used microbial fuel cells. However, the generated power can be distinctly enhanced by using double active layers of pristine carbon nanofiber mats or a single layer Co-doped carbon nanofiber mat as anodes. Typically, after 24 h batching time, the estimated generated power densities were 10, 92, and 121 mW/m2 for single, double active layers, and Co-doped carbon nanofiber anodes, respectively. For comparison, the performance of the cell was investigated using carbon cloth and carbon paper as anodes, the observed power densities were smaller than the introduced modified anodes at 58 and 62 mW/m2, respectively. Moreover, the COD removal and Columbic efficiency were calculated for the proposed anodes as well as the used commercial ones. The results further confirm the priority of using double active layer or metal-doped carbon nanofiber anodes over the commercial ones. Numerically, the calculated COD removals were 29.16 and 38.95% for carbon paper and carbon cloth while 40.53 and 45.79% COD removals were obtained with double active layer and Co-doped carbon nanofiber anodes, respectively. With a similar trend, the calculated Columbic efficiencies were 26, 42, 52, and 71% for the same sequence. [ABSTRACT FROM AUTHOR]

As already mentioned in our article "Hexacyanoferrates (II) belong to an interesting class of sorption materials due to relatively low costs, radiation resistance, high thermal stability, and high selectivity towards cesium [[1]]". Please, let us answer to the comments that Dr. Berek sent in response to our paper. Our results showed that the fibers without impregnation have a small sorption capacity (2 mg Cs SP + sp /L), so in the next step the impregnation was applied to increase it. [Extracted from the article]

As result a bulk mixture of active substance with CF was created, in which the role on CF may be diminished. The authors of paper used large excess of active substances to modify CF. Authors employed microporous carbon fibers (further CF) prepared in our Laboratory by controlled carbonization of delignified cellulose. [Extracted from the article]

Dissolved inorganic carbon (DIC) levels in freshwaters play a key role in the equilibrium of the carbon cycle between the atmosphere, water and living beings. Standard classical methods for DIC determination generally involve bulky and expensive equipment used in centralized laboratories, resulting in time-consuming processes that do not allow for adequate monitoring in the field. In order to address this challenge, we have developed a distance-based paper analytical device (PAD) for on-site determination of DIC in water. The portable, cost-effective and easy-to-use device was based on the miniaturization and integration of a classical acid-base colorimetric titration on a paper channel, enabling an accurate determination of DIC in less than 20 min. The length of the blue colored line in the detection channel after being filled with the sample was related to the DIC concentration in the sample. The reagent solution used to modify the titration channel was optimized so that DIC concentrations in the range 50–1000 mg L−1 could be measured. The long-term stability of the paper-based device was also evaluated, demonstrating a working stability for more than 70 days after their fabrication, an important characteristic for in-the-field analysis. Finally, the PAD was validated with different water samples, i.e. tap water, commercial bottled drinking water and water samples from a mine, with excellent agreement between the results obtained from the PAD and the standard method. This demonstrates the high potential of the proposed paper analytical device to quantify DIC in situ by minimally-trained personnel without the need for peripheral equipment, which represents an important advance compared to the current limited analysis systems. [Display omitted] • Paper-based analytical device (PAD) for dissolved inorganic carbon (DIC) determination. • Portable, cost-effective and easy-to-use device for on-site analysis in freshwater. • Long-term stability over more than six weeks • Validated with tap water, commercial bottled water and mine water samples. [ABSTRACT FROM AUTHOR]

Glutathione and 2-aminopyridine are used as carbon sources to prepare carbon dots (CDs) by a one-step hydrothermal reaction. The results show that the average particle diameter of CDs is 8.64 nm with uniform size distribution and the fluorescence quantum yield is 13.62%. We further demonstrate that novel CDs possess highly selective sensing of Fe3+ from 0.2 to 200 μM with a low detection limit (0.194 μM). Meanwhile, the fluorescence of CDs can be repeated many times by the addition of S2−. Moreover, the CDs are used for biological imaging of living cells with well cell penetrability and low toxicity. Furthermore, it is successfully applied for anti-counterfeiting and information encryption. More interestingly, it can be doped with hydrogel and filter paper to prepare solid-phase sensors exhibiting high sensitivity and fast response, demonstrating their tremendous potential for the simple, rapid, and low-cost monitoring of Fe3+ and S2−. [ABSTRACT FROM AUTHOR]

Sustainability, climate change issues and carbon emissions have recently become more prominent. To limit carbon emissions and reduce them we need to understand where and how much we use. The bridges and viaducts on major infrastructure projects have a high intensity of carbon compared to the average per kilometre. In this paper the carbon footprint of a range of current bridges and viaducts are outlined relative to cost, length, area, material and traffic type to give a benchmark for future reductions and to outline areas where improvements can be made. Engineers have often kept track of material quantities to estimate cost; the carbon content of a bridge can be calculated from the primary material quantities and construction methods. Information from a database of bridges is used in this research to estimate the capital carbon of 200 bridges. The data show the trends for different bridge loading types, materials and spans. The database can be used to assist with the reduction of carbon in bridges by benchmarking current carbon footprints. [ABSTRACT FROM AUTHOR]

Based on the fluorescence quenching principle, a novel lanthanum-doped carbon quantum dots (La-CQDs) fluorescence probe was successfully developed for ion detection of Fe3+. La-CQDs with a fluorescence quantum yield of 29.93% was prepared in ethanol solution using ammonium citrate as the carbon source and lanthanum nitrate as the dopant. The luminescence performance of La-CQDs was enhanced by La doping and maintained over 90% of the maximum fluorescence intensity in different anions, water content and organic solvent environments. In the range of 25–200 μM, the fluorescence intensity of La-CQDs displayed a good linear relationship (Y = 0.00675X+ 1.07679, R 2 = 0.9888) with the concentration of Fe3+ and its limit of detection (LOD) was calculated to be 6.78 μM. The method was successfully applied to the detection of Fe3+ in green tea and the measurement error was less than 3%. In addition, La-CQDs was developed for fluorescent colorimetric test paper and information anti-counterfeiting, while the fluorescence quenching effect was observed intuitively on the paper. Lanthanum-doped carbon quantum dots (La-CQDs) prepared by one-step solvothermal method for Fe3+ detection, fluorescent colorimetric test paper and information anti-counterfeiting. [Display omitted] • A novel lanthanum-doped carbon quantum dots (La-CQDs) was synthesized by a one-step solvothermal method. • The synthesized La-CQDs emitted distinct blue fluorescence with a quantum yield of 29.93%. • A fluorescent colorimetric test paper using La-CQDs for the detection of Fe3+. • Exploring the fluorescence quenching mechanism of La-CQDs using fluorescence information anti-counterfeiting. [ABSTRACT FROM AUTHOR]

The requirement to establish novel methods for visual detection is attracting attention in many application fields of analytical chemistry, such as, healthcare, environment, agriculture, and food. The research around subjects like "point‐of‐need", "hue recognition", "paper‐based sensor", "fluorescent sensor", etc. has been always aimed at the opportunity to manufacture convenient and fast‐response devices to be used by non‐specialists. It is possible to achieve economic rationality and technical simplicity for optical sensing toward target analytes through introduction of fluorescent semiconductor/carbon quantum dot (QD) and paper‐based substrates. In this Review, the mechanisms of anthropic visual recognition and fluorescent visual assays, characteristics of semiconductor/carbon QDs and ratiometric fluorescence test paper, and strategies of semiconductor/carbon QD‐based hue recognition are described. We cover latest progress in the development and application of point‐of‐need sensors for visual detection, which is based on a semiconductor/carbon quantum dot‐based hue recognition strategy generated by ratiometric fluorescence technology. [ABSTRACT FROM AUTHOR]

Wood research has recently enjoyed a renaissance due to its emerging application in various fields. This is due to the natural reaction platform and hierarchical porous structure of wood, which allows it to combine perfectly with functional materials, especially nanoscale materials. Here, we report a portable fluorescent wood (FW) test paper based on the combination of wood and carbon dots (CDs) for rapid identification and detection of nitroaromatic explosives. Thereinto, the CDs optimize the assembly of wood and open up new functions, and the naturally porous structure of wood provides grid management for CDs, effectively avoiding the accumulation of CDs. Meanwhile, the CDs are immobilized in the wood skeleton via the multiple-blockades, and the fluorescence intensity is unaffected even under harsh environmental conditions, which ensures the FW test paper exhibits high sensitivity and selectivity for trinitrophenol. The quenching reached 100% by dropping 80 μM trinitrophenol with the ultrathin FW test paper (1 × 1 × 0.009 cm), and it is still significant in the presence of interference. Interestingly, the detection results can be monitored in real time with the naked eye. As far as we know, this is the first report of trinitrophenol detection with FW test paper. Illustration of proposed wood-based colorimetric test paper is encapsulated with fluorescent carbon dots for explosive detection. [Display omitted] • Fluorescence wood (FW) test was reported based on wood-nano and carbon dots. • FW test paper performed high sensitivity and selectively for TNP detection. • The TNP detection results can be directly observed by naked eye. • FW test paper showed excellent resistance performance in harsh environment. [ABSTRACT FROM AUTHOR]

Two instrument-free boron, nitrogen-doped carbon dots based fluorescent solid sensors (i.e. , test strips and hydrogel beads) are fabricated to sensitively monitor both Cu2+ and Co2+. [Display omitted] • Novel B, N co-doped carbon dots (BN-CDs) with bright tangerine fluorescence are solvothermally fabricated. • BN-CDs effectively detect both Cu2+ and Co2+ with high sensitivity and a low detection limit. • The joint effect of dynamic and static quenching mechanisms is proposed for fluorescence quenching by Cu2+/Co2+. • The BN-CDs based paper sensors exhibit rapid and sensitive response for Cu2+/Co2+ in an instrument-free manner. • The fluorescent BN-CDs/hydrogel conduct as sensor to sense Cu2+ and Co2+, and absorbent for removal of the ions. It is highly significant to develop water-soluble carbon dots (CDs) for ion detection in the environment via a facile and economical process. Herein, the organic molecules derived boron, nitrogen co-doped CDs (BN-CDs) with water-solubility are solvothermally synthesized towards dual ion detection. The BN-CDs emit bright tangerine fluorescence, and demonstrate a fluorescent quantum yield of 17 %. Besides, the obtained BN-CDs show a good linear relationship with Cu2+/Co2+ in a wide dynamic range of 1–8 μM, along with detection limits of 16 nM (Cu2+) and 24 nM (Co2+). The joint effect of dynamic and static quenching mechanisms is proposed as well for fluorescence quenching by Cu2+/Co2+. Furthermore, two instrument-free BN-CDs-based solid sensors (i.e. , test strips and hydrogel beads) are fabricated to sensitively monitor both Cu2+ and Co2+. The paper-based sensors exhibit selective and sensitive response towards Cu2+ and Co2+ in a low-cost manner. The fluorescence hydrogel integrates comprehensive advantages of hydrogel and BN-CDs, which makes it not only conduct as efficient fluorescent sensors to detect Cu2+ and Co2+ but act as the absorbent towards removal of the ions. The simple yet reliable sensing technique developed here favor efficiently detecting and recognizing dual ions in environmental and/or biological samples. [ABSTRACT FROM AUTHOR]

The surface of paper was treated to control wettability using argon-carbon plasma generated by a direct current-pulsed (frequency: 60 kHz) sputtering device with parallel-arrangement magnets. After plasma treatment, the C–C bond percentage in the C 1s region was inversely proportional to the C–OH bond percentage, while the ratio of C=O and O–C=O bonds only changed slightly. The change ratios for the increase in C–C and the decrease in the C–OH bonds were approximately the same, and the change ratio increased from approximately 5%–11% with an increase in the plasma current. The reduction ratio of the contact angle decreased from 0.945 to 0.182 (°/s) with increasing plasma current. These results indicate that the water resistance of the paper surface was enhanced after the simple plasma treatment, and wettability could be easily controlled by changing the substitution ratio between C–OH and C–C elements, achieved by altering the plasma current. • Papers were plasma-treated using DC-pulsed sputtering with parallel-aligned magnets. • C–C and C–OH bond percentages were inversely proportional after plasma treatment. • Substitution ratio between C–OH and C–C was changed by varying the plasma current. • Contact angle reduction ratio on paper decreased with increase in plasma current. [ABSTRACT FROM AUTHOR]

Most fluorescent probes based on carbon dots (CDs) fluorescence color or intensity change are still used for detection in solution, but in practical fluorescence detection applications, detection in the solid state is necessary. Therefore, a CDs-based fluorescence sensing device is designed in this paper, which can be used for water detection in liquid and solid states. Using oPD as a single precursor, yellow fluorescent CDs (y-CDs) were prepared by hydrothermal method, which can be used in the field of water detection and anti-counterfeiting by using its solvent-sensitive properties. First, y-CDs can be used to visually and intelligently detect the water content in ethanol. Secondly, it can be used to detect the Relative Humidity (RH) of the environment by combining it with cellulose to form a fluorescent film. Finally, y-CDs can also be used as a fluorescent material for fluorescence anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Sustainable development has become society's focal point. In this context, China's paper industry needs to be more concerned about a low‐carbon strategy. Therefore, a carbon performance evaluation system must be built to guide the low‐carbon enterprise transformation. Based on the carbon value flow analysis, this study takes JX Paper (a paper‐making enterprise) as an example to construct a carbon performance evaluation system consisting of carbon input, transfer, and output indicators. The quantitative and qualitative index weights were determined through a principal component analysis and an analytical hierarchy process. The overall carbon performance increased from 2012 to 2021, but room remains for improvement. These results show that the performance evaluation system provides a helpful reference for enterprises to identify the key factors affecting carbon emissions and evaluate their carbon performance. Moreover, objective criteria should be developed to improve sustainable enterprise carbon performance and low‐carbon competitiveness. [ABSTRACT FROM AUTHOR]

Wood has always been an indispensable material in human society throughout history. Its efficient utilization is even more crucial today in achieving the Sustainable Development Goals (SDGs). However, its production, trade, use, and recycling are seldom systematically assessed, with Germany being an exception due to the extensive work conducted by the University of Hamburg and the Thünen Institute over the years. To provide a more precise account of wood use, this study employs oven-dry metric tonne as the reference unit to construct a static wood flow based on the material flow analysis and wood resource balance in Germany in 2020. The Sankey diagrams comprehensively visualize the flow and stock of wood in various sectors, including forests, sawmills, pulp mills, buildings, energy, and waste. Results showed that forest felling volume exceeded growth due to significant wood demand and export, while forest carbon sinks increased because more hardwood was retained in German forests. The building and construction sector was the largest consumer of primary wood products, accounting for 52.1 % of the total, followed by furniture (29.5 %) and packaging (14.0 %). All waste paper was used to produce recycled fiber pulp, whereas only 14 % of waste wood was employed in particle board production. The woody biomass energy, amounting to 142.4 TWh, provided approximately 4.4 % of Germany's primary energy consumption, with around half of it used in private households. In addition to apparent data, this study also uses resource allocation, carbon storage, and cascade potential as examples to demonstrate that wood flow is applicable for further in-depth analysis, supporting wood efficient utilization. It can even be applied to any country and period with sufficient data and conversion factors, but here, they also prevented this study from comprehensively describing past and future wood flows. [Display omitted] [ABSTRACT FROM AUTHOR]

Aquaculture is increasing globally, providing protein to a growing population, but little is known regarding the nutrient budgets in aquaculture. To obtain insight into how management practices impact nutrient fluxes in freshwater aquaculture earthen ponds worldwide, we conducted a literature review. Our literature search yielded 23 papers in which nutrient budgets were reported. Our results showed that the main nutrient inputs are inlet water, feed, and fertilizers, but they varied according to location and management practices. Overall, feed and fertilizers constituted the predominant nutrient sources, accounting for up to 99% of the total inputs. The most quantified outputs were outlet water, fish, and sedimentation. Our findings indicate that only up to 20% of carbon, 45% of nitrogen, and 60% of phosphorus are assimilated by the fish. In some systems, up to 80% of carbon, 80% of nitrogen, and 60% of phosphorus accumulate in pond bottoms; in other systems, the outflow represents substantial losses of up to 16% of carbon, 76% of nitrogen, and 55% of phosphorus. More insight into nutrients' fate in fishponds is crucial from a sustainability perspective, as feed and fertilizer use can likely be optimized, reducing operational costs and the potential impact on the surrounding environment and atmospheric greenhouse gas concentrations. [ABSTRACT FROM AUTHOR]

With the improvement of people's living standards and the widening of circulation channels, the demand for fresh agricultural products continues to increase. The increase in demand will lead to an increase in delivery vehicles, costs, and carbon emissions, among which the increase in carbon emissions will aggravate pollution and is not conducive to sustainable development. Therefore, it is very important to balance economic and environmental benefits in the distribution of fresh agricultural products. Based on the analysis of the distribution characteristics of fresh agricultural products, this paper studies the optimization of the cold chain distribution route of fresh agricultural products considering carbon emission. Firstly, the cold chain distribution route planning of fresh agricultural products was investigated and analyzed by the interview method, and the basis for establishing the model objective and constraint conditions was obtained. Then, taking the minimum total cost including carbon emission cost as the optimization goal, the cold chain distribution route optimization model for mixed vehicle types is established considering electric refrigerated vehicles, gasoline refrigerated vehicles, and so on. Genetic algorithm was used to solve the model, and MATLAB2018b was used to substitute specific case data for simulation analysis. The analysis results show that increasing the consideration of carbon emission and mixed vehicle types in the distribution route of fresh agricultural products can not only reduce the distribution cost but also reduce the carbon emission. To some extent, the research content of this paper can provide a reference for enterprises in planning cold chain distribution routes of fresh agricultural products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sensitive : carbon dots were sensitive to pyrimethanil (PMT) yielding LOD of 14 nM. • Selective : carbon dots were selective to PMT against several interferences. • Accurate : concentrations of PMT in real samples were accurately determined. • Reusable : paper-based sensor produced excellent results even after 8-time uses. • Fast : the sensor gave the detection results within 30 s. Novel sensors based on fluorescent carbon dots were developed for a rapid, selective, and sensitive detection of pyrimethanil, a fungicide widely used in many agricultural crops. The carbon dots were synthesized from maleic anhydride and triethylenetetramine via a facile one-pot pyrolysis. A quenched fluorescence intensity of carbon dots in the presence of pyrimethanil occurred via inner filter effect and strong π-π interaction. The carbon dots were sensitive to pyrimethanil across a linear range from 0.5 to 75 µM with a low detection limit of 14 nM. The sensing results could be generated in 30 s. The fluorescent carbon dots showed excellent stability and selectivity to pyrimethanil in the presence of interferences, including fungicides and metal ions. They were also successfully employed for pyrimethanil detection in apples, cucumbers, and drinking water, yielding 98.6–107.1% recovery. The practical, portable, and reusable paper-based sensor was also developed. The cytotoxicity of carbon dots was tested to demonstrate that they are sufficiently safe to use. The novel pyrimethanil sensor based on fluorescent carbon dots developed in this work can be used as a high-performance sensor and a rapid tool for quality control in food, agricultural, and environmental monitoring. [ABSTRACT FROM AUTHOR]

[Display omitted] • By slow pyrolysis, pulper waste is converted into a stable, carbon-rich material. • Chemical leaching upgrades the carbon-rich solid to a fossil coal substitute. • The process enables to recover more than 90 % of Ca and Al from pulper waste. • By precipitation, a reusable Al-based flocculating agent is obtained. • Clean hydrogen is produced by the reaction between metallic Al and HCl. This work aims to investigate the potentials of integrating slow pyrolysis and chemical leaching to recycle pulper waste (PW), the waste generated by paper mills, and consists of plastics, metallic films, and biobased polymers. The concentration of chlorine and metals is a barrier against PW valorisation by combustion or high temperature thermochemical processes. In this study, PW was tested by slow pyrolysis at 400 °C and 500 °C. Chemical leaching tests were performed by processing both chars in a 1.4 M HCl solution, at 80 °C for 2 h, to remove inorganic compounds and upgrade the char to a coal-like material. Then, precipitation by NaOH was conducted on the leachate. Slow pyrolysis led to a char mass yield around 30 %. Due to the high inorganic matter concentration (almost 36 %, mainly including chlorine, calcium, and aluminium), the char retained only 25 % of the feedstock's chemical energy, while the remaining 75 % was recovered in the pyrogas. Leaching of the 500 °C pyrolysis char led to extract 93 % of aluminium, and almost 100 % of calcium and chlorine, resulting in an upgraded char containing 15.5 % ash, comparable to a fossil coal. By char leaching, the oxidation reaction of aluminium could produce 8 kg hydrogen per dry ton PW. The effectiveness of the precipitated compounds as flocculating agents was demonstrated, enabling a closed-loop recycling in the same paper mill. In conclusion, the proposed process demonstrated to be an effective solution to convert PW into high quality products. [ABSTRACT FROM AUTHOR]

Owing to unique physical and optical properties, fluorescent carbon dots (C-dots) are used in various biomedical applications. In this study, C-dots have been integrated as sensing agent on paper surface for colorimetric determination of clinically important analytes. Polyacrylamidebased C-dots coated C-dips showed visible color change from white to brown for iron (Fe2+, Fe3+) sample. Moreover, iron and copper (Cu2+) samples showed significant quenching of C-dots under UV. Images captured with/without UV were analyzed to study the relationship between different iron and copper concentrations and colorimetric intensity values. Color intensity and fluorescence showed a linear relationship with concentrations of iron and copper (Range: 1×10-4 to 1×10-2 M, Linearity: R² = 0.94). LOD from the paper sensor showed a sensitivity of 3.89×10-5 μM, 4.65×10-5 μM and 6.7×10-5 μM for Fe3+, Fe2+ and Cu2+ respectively, reflecting its reliability as low-cost sensing solution to analyze clinically relevant analytes as reported in current study. [ABSTRACT FROM AUTHOR]