In this study, disk-shaped copper sulfide nanoparticles (CuS-NPs) were synthesized via a simple co-precipitation method and used as a photocatalyst for the reduction of carbonate species derived from marble dust into acetic acid (AcOH). The photocatalytic reaction was carried out under monochromatic light (525 nm) in a hydrogen peroxide-water mixture using CuS-NPs. Key parameters such as solvent composition, light source, catalyst concentration and reaction time were optimized to get the maximum yield of AcOH. The reaction mechanism was investigated using radical scavenging experiments. The practical applicability of the approach was further tested on two additional real-life carbonate waste materials, i.e., chalk dust and carbonate scale.

Herein, we have synthesized a three-dimensional and hydrophobic graphene incorporated carbon aerogel (G-SCA) derived from sugar. G-SCA is being used as a multifunctional sorbent material for removing various advanced water-soluble and insoluble pollutants. Initially, G-SCA is being explored for the adsorption of nitroarenes (nitrophenols, 3-nitroaniline), an insecticide (Phoskill), an antibiotic (ciprofloxacin), and a pharmaceutical drug precursor (pyridine). Later, the same G-SCA is also explored in the absorption of various protic and aprotic organic solvents, and oils (including crude oil, waste cooking oil, and waste engine oil), with excellent recyclability checked up to 10 cycles. Moreover, oil-water separation experiments are also being done in various industrial wastewater and seawater samples to support the real-life accessibility of the present approach. Large-scale applicability of G-SCA is also checked by performing crude oil-seawater separation experiments using a laboratory-scale prototype demonstrating the successful continuous recovery of crude oil.

Herein, we have described a simple and viable approach to use the waste byproduct of steel industries: red iron oxide dust (IOD) for synthesizing its reduced version as reduced-IOD (r-IOD). The r-IOD possess active multiphases of iron oxides (Fe@Fe3O4@Fe2O3) and is used for the adsorption of three organic dyes. The surface area of magnetically active r-IOD is found to be ∼4.5 times than that of IOD and shows better mesoporosity. Due to having a larger surface area, r-IOD is used for the efficient adsorption of three organic dyes that include two anionic azo dyes, namely, RG 19 (Reactive Green 19), RO 16 (Reactive Orange 16) and one cationic MG (Malachite Green) dye, with maximum adsorption capacities of ∼2162.9, ∼2273.1, and ∼1400.2 mg g–1, respectively. Various batch experiments related to kinetics, isotherms, and adsorption thermodynamics are studied to understand the rate, order, type, and feasibility of adsorption. The effects of temperature, pH, loading, and concentration, on the adsorption process are also investigated. Moreover, the adsorption capacity of r-IOD is satisfactorily tested via an external spiking method toward the dye removal from industrial wastewater and laboratory wastewater.

Iron oxide dust, discarded as industrial waste, has been used here to fabricate magnetic iron oxide nanoparticles (Fe3O4-NPs). We have proposed the thermo-catalytic reduction of carbon dioxide (CO2) using Fe3O4-NPs in the presence of H2O2 to get acetic acid (AcOH) at near ambient conditions (100 °C, 10 bar) with a maximum yield of ∼0.4 M in a batch-reactor. The importance of H2O2 can be described as it facilitates the production of higher concentrations of OH˙ and H+/˙, which consequently supports the synthesis of AcOH.

Herein, we report a single-step carbonization approach for fabricating high-performance three-dimensional (3D) porous and superhydrophobic carbon-aerogel (S-CA) from edible sugar. S-CA has been used here to remove many substances, including various solvents (polar protic and aprotic, nonpolar, and oily), oils (crude, engine, waste cooking oil, etc.), and nitroaromatics (p-nitrophenol, dinitrophenol, 3-nitroaniline, and 4-nitroaniline) compounds based on their adsorption abilities. The superhydrophobic nature of porous S-CA has been supported by a static contact angle of ∼155° and the formation of a silver mirror-like surface when contacted with the surface of the water. S-CA adsorption capabilities were used to separate crude petroleum oil, waste engine oil, and a few other types of waste oil (waste cooking, silicon oil, and mustard oil) from the aqueous medium. Moreover, absorption analyses were extended to the adsorption and recovery of the toxic nitroaromatic pollutants from the aqueous medium. The nitroaromatics were recovered from the S-CA using ethyl acetate with a percentage recovery of more than 95%. Kinetic and intraparticle diffusion studies are being studied to understand the type and various stages of adsorption.

Herein, we propose a simpler synthesis of low-cost multiphase reduced iron oxide nanoparticles (r-IOD) as (Fe@Fe3O4@Fe2O3), which have been synthesized from steel-industry-liberated iron oxide dust (IOD) via a one-pot chemical reduction method. These r-IOD have effectively catalyzed the aqueous phase reduction of 4-nitrophenol (PNP), 2,4-dinitrophenol (DNP), and 2,4,6-trinitrophenol (TNP) to their respective amine derivatives in the presence of sodium borohydride notably at room temperature. A plausible mechanism is also been proposed based on the UV-visible absorption of intermediates and the XRD analysis of the spent catalyst.

Herein, we describe the possibility of using solid CO2, also known as dry ice, as an exfoliating agent for thermal-assisted exfoliation of graphite. Used dry ice has been chosen over supercritical CO2 for its easy availability after storage purposes. HRTEM analysis showed the increased spacing between the stacked graphite layers after exfoliation. BET and Raman analyses provided evidence for an increased surface area and quantity of defects for the exfoliated graphite powder. VSM analysis showed a ∼three-fold improvement in magnetization in the exfoliated graphite powder sample compared to the control.

Herein, we have synthesized zinc oxide (ZnO) particles from the zinc ash generated as waste in the galvanization process in the steel industry, ZnO particles were decorated with copper oxide (CuO) nanoparticles, and then further activated by reducing them to get a heterojunction photocatalyst (ZCu@ZnO). Thereafter, ZCu@ZnO is utilized for the photoreduction of carbonate to acetic acid (AcOH) in a H2O2-water mixture as a hydrogen-rich solvent under the illumination of various light sources. Moreover, various physical and chemical parameters, such as solvent mixture, light sources (monochromatic lights and sunlight), photocatalysts, time, etc., were also optimized to get the maximum yield of AcOH (∼0.47 M). The mechanism of photoreduction of carbonate to AcOH is also being proposed based on scavenging experiments of free radicals.

Herein, waste-derived copper (Cu) flakes have been used as heterogeneous catalysts for the solvent-free and one-pot reductive acetamidation of nitroarenes. Metallic copper flakes (f-ZCu) were isolated from waste copper Cu scrap/flakes/turnings generated after the grinding and cutting (from the Cu industries). f-ZCu is being used to synthesize acetanilide with a considerable yield (∼82%) in one-step and solvent-free conditions within a reaction time of 6 h. Moreover, the same procedure is also being utilized for producing various substrates (9), including the gram-scale synthesis of the well-known important antipyretic drug, i.e., paracetamol. The plausible mechanism for the reaction was also proposed based on the spectroscopic analyses of spent f-ZCu.

The global challenge concerning carbon dioxide (CO2) conversion to valuable products is anticipated to execute an essential task towards net zero carbon emissions. Thermal CO2 reduction is advantageous in terms of higher conversion rates, selectivity, and already-established thermal instruments for scalability. However, the method is energy-intensive, a hindrance to sustainably practical adoption. Herein, we present a comprehensive study of H2O2-mediated thermal CO2 conversion in the presence of dendritic zerovalent copper (d-ZCu) in a batch-type reactor, yielding C1 and C2 carbon products, with acetic acid (AcOH) as the major product (achieving an optimized yield of approximately 0.98 M and a selectivity of around 97 % at near ambient conditions of 25–150 °C and 1–15 bar), along with trace amounts of methanol (MeOH) and ethanol (EtOH), and carbon monoxide (CO) as a gaseous product. The reaction parameters, including temperature, time, pressure, and concentrations, were optimized to gain better insight into the reaction. To further explore the feasibility of the process, experiments were performed in a continuous flow-packed bed reactor using similar parameters as those in the batch reactor, where CO was identified as the major product of CO2 reduction. For advanced real-life applicability, the as-emitted exhaust gases from diesel and petrol engines, as sources of anthropogenic CO2, were utilized to establish the practical applicability of the proposed method.

Herein, we explored a simple approach to using readily available low-cost industrial waste from steel industries known as red-colored iron oxide dust (IOD). After that, it was used for the sunlight-assisted photo removal of another toxic waste material (hexavalent chromium (Cr(VI)) from the aqueous medium showing the photo-Fenton-type mechanism, importantly without using hydrogen peroxide. The photoactive properties of chemically reduced IOD (r-IOD) have been explored to remove toxic Cr(VI) in the presence of two different sources of light (sunlight and artificial bulb light). Kinetic studies and various control experiments have been performed to check the comparative photocatalytic performance of IOD versus r-IOD nanoparticles. The values of the half-life of Cr(VI) removal strongly support the significant influence of the sun on the faster rate for the removal of ∼250 mg L-1 Cr(VI). To maintain the lower pH needed for Cr(VI) reduction, a small quantity of formic acid was used, which can be removed easily by forming CO2 and H2O. The radical trapping experiments and spectroscopic investigations of residue products obtained after the photoreduction process have been explored to support the mechanistic investigation involved in the sunlight-promoted photoreduction of Cr(VI).

Here, we describe a simpler-sustainable approach for fabricating photo-active magnetite nanoparticles (Fe3O4-NPs) using an almost inert waste material known as red-colored iron oxide dust (IOD). The synthesized heterogeneous catalyst Fe3O4-NPs showed photoactivity in the presence of sunlight and was used for photodegradation of a higher concentration (∼1000 mg L-1) of noxious nitrophenols and their mixtures in an aqueous medium. Kinetic studies, including control tests, have been performed to compare the photocatalytic performance of Fe3O4-NPs vs IOD in sunlight and artificial bulb light. The half-life and percentage of photodegradation strongly suggest that sunlight influences the faster rate of photodegradation of nitrophenols and their mixtures. Radical trapping experiments were performed to identify the reactive active species responsible for the photodegradation, and the results support the significant involvement of hydroxyl radicals along with holes. Further, the real-life assessment of Fe3O4-NPs as a photocatalyst was explored by checking its photodegradation capability in industrial wastewater and soil samples via the external spiking of nitrophenols. Moreover, the results are compared with two commercially available samples of Fe3O4, which showed almost comparable results, and in the case of trinitrophenol (TNP) and the mixture, synthesized Fe3O4-NPs showed slightly better results. The quantitative studies of green chemistry metrics and DOZN software-based calculations supported the greener and more sustainable process of the present method for the synthesis of Fe3O4-NPs.

A simple and single-step synthetic protocol is reported here for synthesizing medicinally important amide compounds such as acetanilide (N-phenylacetamide) and its derivatives (including paracetamol and phenacetin). Compared to the existing reports used for a single-step amidation that requires multiple reagents, herein, waste-derived iron nanoparticles (FeOx-NPs) isolated from the “free-of-cost available iron dust/powder” were used for the same single-step amidation reaction without using any external reagents and high pressure, resulting in the cost-effective viable reported procedure. The Soxhlet-purified iron dust is subjected to high-temperature heating at ∼800 °C in a muffle furnace to achieve its heterogeneously active form (Fe3O4-type moieties on its surface). The as-prepared catalyst (FeOx-NPs) has been used to synthesize 17 acetanilide derivatives including two essential antipyretic drugs, paracetamol and phenacetin, on a gram scale, and one industrially important dye/pigment precursor (2-nitroacetanilide). Based on the X-ray photoelectron spectroscopy and vibrating sample magnetometry results, a possible mechanism has been proposed. The sustainability associated with the whole process is the direct amide formation using a magnetically separable waste-derived metal catalyst in solvent-free conditions, which provides a possible way to utilize large-scale industrial waste, thus directly reducing some environmental stress.

Herein, we described a cost-effective, viable methodology for using an iron-based industrial waste material known as iron oxide dust (IOD), also known as Hematite (α-Fe2O3) for the synthesis of their chemically reduced magnetic version named r-IOD (Fe3O4@α-Fe2O3). r-IOD showed its visible-light-promoted photoresponsive behavior for the photodegradation of higher concentration (∼1000 mg L-1) of five different model dyes (methyl orange (MO), metanil yellow (MY), Congo red (CR), methylene blue (MB), crystal violet (CV), and their mixtures) in the presence of sunlight. Based on kinetic and radical trapping experiments, mechanistic analysis supports the significant involvement of superoxide radicals responsible for the photodegradation. Moreover, different industrial and soil samples were externally spiked with dyes and further analyzed for a similar set of photodegradation experiments to support the viability of the reported procedure, concerning the utilization of waste materials.

The MoS2-based reduced graphene oxide aerogel (MoS2-rGOA)-assisted organic transformation reactions are presented. MoS2-rGOA is used as a heterogeneous catalyst for the reduction of benzene derivatives such as benzaldehyde, nitrobenzene, and benzonitrile to benzyl alcohol, aniline, and benzamide and their derivatives, respectively, in green solvents (water/methanol) and green reducing agents (hydrazine hydrate having N2 and H2 as byproducts). The mechanistic features of the reduction pathway, substrate scope, and the best suitable conditions by varying the temperature, solvent, reducing agent, catalyst loading, time, etc. are optimized. All of the synthesized products are obtained in quantitative yield with purity and well characterized based on nuclear magnetic resonance analysis. Further, it is also observed that our catalyst is efficiently recyclable and works well checked up to 5 cycles.

The improvements associated with developing newer pathways for the catalytic reduction of carbon dioxide (CO2) into valuable products have grown a lot in recent times. Herein, we investigated the possibility of using waste red-colored iron oxide dust (IOD) as a low-cost available precursor for synthesizing magnetic black-colored iron oxide nanoparticles (Fe3O4-NP). The as-synthesized Fe3O4-NP has been used to thermo-catalytically reduce CO2 to carbon monoxide (CO) using the well-known process of reverse water gas shift reactions (RWGS) with a > 97 % selectivity with ∼ 22 % CO2 conversion. The catalytic activity of Fe3O4-NP for converting CO2 into CO has been analyzed in a laboratory-scale continuous fixed bed reactor, where Fe3O4-NP showed better results than IOD. The electrochemical studies have also supported the improved RWGS activity of Fe3O4. Additionally, the catalytic activity of synthesized nanoparticles for RWGS has been compared with two commercially available samples of Fe3O4 named CS1 and CS2, where the synthesized Fe3O4-NP showed better results, which advocates the suitability of the reported procedure related to the utilization of iron-based industrial waste.

A simpler approach of functionalization for the fabrication of thiourea-functionalized-Graphene Aerogel (t-GA) is described here. Graphene Aerogel (GA) was synthesized from bio-mass, which on a simpler oxidative treatment get converted to its water-soluble version due to the impregnation of several oxygenous functionalities like carboxylic, hydroxyl, etc. Further, these carboxylated groups have been functionalized with the molecules of thiourea using the long known dicyclohexylcarbodiimide (DCC) as a coupling agent. The as-synthesized t-GA shows bright yellow fluorescence with a quantum yield of ~3% and holds the high-aqueous solubility and photostability. The fluorescence property of t-GA has been used here for the specific and selective sensing of toxic lead (Pb(II)) metal ions from the used many other metal ions via the fluorescence quenching and showed a limit of detection ~7.3 nM. Further, the mechanism for selective sensing was studied in detail and found to be preferable via ligand to metal charge transfer quenching mechanism. The cyclic voltammetry studies supported the selective sensing of Pb(II). Moreover, t-GA has also been studied for the sensing of hydrogen peroxide and as a yellow fluorescent ink.

Herein, a simpler-viable methodology for the surface decoration of pear fruit derived graphene aerogel (GA) via cadmium sulfide (CdS) has been presented. GA can be easily synthesized from bio-mass, which provide an economic advantage. Surface decoration via CdS imparts photocatalytic activities in functionalized graphene aerogels (f-GA). CdS-f-GA is being explored here as a photocatalyst for the degradation of a toxic azo dye named Congo red in the presence of sunlight. The rate and mechanism associated with photodegradation were analyzed by performing kinetics and radical trap-based quenching experiments. Nuclear magnetic resonance and fourier transform infrared spectroscopy analyses of the control and photodegraded products were performed to ensure the degradation of the organic framework of Congo red. Additionally, the real-life applicability of CdS-f-GA was also analyzed by degrading the dye in different types of industrial samples (via the method of external spiking), which can advance its practical relevance.

A sustainable approach for the rapid synthesis of red-emissive doped carbon dots (r-CD) from the leaves extract of an Indian medicinal plant known as Bael (Aegle marmelos) is described here. The fabrication process involves the solvent-based extraction using the mixture of ethanol:water (1:1), followed by the carbonization of extract in the domestic microwave to obtain r-CD without using extra chemical reagents. The as-prepared self doped r-CD exhibit the excitation-independent emissive profiles, importantly in the red region of visible spectrum with a high-quantum yield value of ~ 56% and good colloidal stability. The r-CD are used here as a fluorescent probe for the detection of toxic hexavalent chromium (Cr(VI)) ions which is considered as one of the most toxic pollutant materials. The selective sensing of Cr(VI) was performed via the method of fluorescence quenching of r-CD by Cr(VI), with lower limit of detection ~ 900 nM. Additionally, r-CD was further being evaluated as a fluorescent ink that could be used for printing and security purposes.

Herein, a simple-functionalization method is described to prepare the oleylamine functionalized non-aqueous version of onion-like nanocarbons (ONC-OA), where ONC was isolated from the waste pollutant soot exhausted from the diesel engine. The surface group analysis of ONC-OA has been investigated via Nuclear Magnetic Resonance and X-ray Photoelectron Spectroscopy. ONC-OA shows blue fluorescence with a quantum yield of ∼6% in tetrahydrofuran (THF). The fluorescence-based sensing applications of ONC-OA has been investigated for selective sensing of toxic aromatic nitro-phenols compounds (para-nitro, dinitro, and trinitro phenols) from the tested many nitro organic compounds. Based on the limit of detection values, ONC-OA shows much better results for tri-nitro phenol compared to di and mono nitrophenol. To understand the quenching mechanism, a time-resolved photoluminescence analysis of the sensor with and without the addition of quenchers is performed. The effective lowering in fluorescence lifetime of the sensor after the addition of quenchers concludes that the quenching observed is majorly due to the Förster Resonance Energy Transfer (FRET) mechanism. The real-life application of ONC-OA was analyzed by external spiking of N-PhOHs in soil samples.

Nitroaromatic compounds (NACs) have been polluting the soil and groundwater via anthropogenic activities. Due to their well-known explosive and toxic nature, their selective-sensitive detection specifically 2,4,6-trinitrophenol (TNP) and 2,4-dinitrophenol (DNP) become essential. Herein, hydrophobic carbon nanoparticles (HCNPs) have been synthesized by a single-step and simple methodology by refluxing maleic acid in the presence of oleylamine. The as-synthesized HCNPs possess a spherical shape with a diameter of 60 ± 5 nm and is insoluble in an aqueous medium but soluble in non-aqueous solvents. HCNPs show brightly blue emission at ∼464 nm with ∼24% quantum yield. The fluorescence property of HCNPs is applied towards the selective sensing of NACs. The fluorescence intensities of HCNPs have been significantly quenched selectively only after the addition of TNP and DNP from the tested many NACs. The detection limit of HCNPs for TNP and DNP is low as ∼242 nM and ∼276 nM, respectively. Concerning the plausible mechanism of selective fluorescence-based detection, TNP/DNP molecules interact with HCNPs, which involves the dynamic quenching behavior with both the Förster resonance energy transfer (FRET) and photo-induced electron transfer (PET) process.

Herein, fabrication of a functionalized graphene aerogel (f-GA) from a biomass (pear fruit)-derived graphene aerogel (GA) is described. Functionalization showed a prominent effect that results in the improved adsorption capacity of f-GA compared to GA, and even better (∼more than double) than commercially available activated carbon (AC). f-GA has been studied for the removal of three different model pollutant dyes, namely crystal violet (CV), methylene blue (MB), rhodamine B (RhB) and their mixtures, along with it also being used for dye removal from unknown real industrial samples. Moreover, a detailed comparative analysis showed the adsorption capacity of f-GA towards CV, MB, and RhB has been improved up to ∼6, ∼7, and ∼10 times, respectively, compared to that of control GA. The recyclability of f-GA was also tested: it works for five cycles without losing its apparent performance.

Herein, a simpler isolation method has been proposed for using the loosely adsorbed surface-adhered waste from the surface of pollutant diesel soot (DS). The simple extraction protocol is based on Soxhlet-purification using acetone to extract the acetone-soluble fluorescent fraction from the bulk DS. The acetone soluble fraction contains some fraction that should be soluble in aqueous medium. So a gel-separation technique was used to separate the highly fluorescent water-soluble fraction of nano-carbons from the bulk. Transmission electron microscopy analysis reveals the carbon dot (CDs) like morphology of the as-extracted blue-green fluorescent water-soluble fraction. These CDs show strong fluorescence photostability (checked up to 4 hours) and have ∼8% quantum yield. The fluorescent water-soluble CDs are used for the selective sensing of Fe(iii) and toxic-Hg(ii) metal ions among most all the tested metal ions. To determine the plausible quenching mechanism, spectral overlap analysis and time-resolved photoluminescence analysis were performed. The fluorescence quenching by Fe(iii) was mainly attributed to the inner filter effect (IFE) mechanism while in the case of Hg(ii) ions, quenching was because of the ligand to metal charge transfer (LMCT) mechanism. The sensing of metal ions was additionally supported with the aid of cyclic voltammetry analysis. This journal is

Herein, we provide a possible description for the isolation/fabrication of nanocarbons from freely available global pollutant waste as black-carbonaceous-soot particulates known as black carbon (BC). It is important to mention here that BC contains many different types of nanocarbons, which have routinely been formed during combustion and were further admixed with air, and therefore enhancing the possibility of global warming. Nevertheless, the different composition and burning condition of fuel results in the emission of different-sized–shaped soot particulates. BC particulates are generally divided into two categories, i.e., indoor and outdoor BC. A possibility has been discussed here to develop some more easily accessible isolation methodologies for the extraction of nanocarbons from BC, explicitly with the expectation to use them for fruitful purposes. Additionally, it will also contributing in improving the overall air quality. In particular, this review summarizes the spectroscopic and microscopic identifications of nanocarbons isolated from the different types of indoor and outdoor BC particulates. Further, in subsequent sections, we have discussed their possible applications, like sensing, bioimaging/biological activity, adsorption, photocatalysis, energy storage devices, agricultural uses, photonics, superamphiphobic material, etc.

A simple and sustainable approach is described for the synthesis of photoactive carbon dots (CD) as an efficient photo-catalytic material. The photoactive-CD has been fabricated by simply charring the peels of Bitter Apple (BA). It is somewhat similar to the biochar synthesis. The photoactivity of BA peel derived photoactive-CD was tested under the illumination of sunlight for photodegradation of a pollutant organic dye, crystal violet (CV). A possible mechanism has been proposed for photodegradation of dye based on the trap experiment, where electron and holes were majorly responsible. BA peel derived photoactive-CD showed remarkable results concerning the photodegradation of CV (20 ppm in ~ 90 min) under sunlight illumination as compared to the dark conditions.

Presently, the technologies associated with using waste materials for the fabrication of newer useful materials have been greatly advanced. For the same purpose, a possible sustainable approach is described for the utilization of globally available dirty dangerous material, known as black carbon (BC), in the form of particulate diesel soot. From the black diesel particulate matter, onion-like nanocarbons (ONC) have been isolated followed by their surface functionalization to yield their amine-functionalized water-soluble version as ONC-NH2, which exhibits a high quantum yield value of ∼20%. Concerning the synthetic protocol, the potential associated with the presented report reveals that these ONC were used without being explicitly synthesized. These were just isolated from the diesel soot, which on amine functionalization have been converted to an efficient, biocompatible fluorescent probe for the imaging of cancer (HeLa) cells and selective sensing of toxic chromium Cr(VI) in water. The detailed surface functionalization by the amine molecules in ONC-NH2, which make them readily soluble in aqueous media, is investigated using several spectroscopic techniques such as XPS, NMR, and FTIR.

The presented finding offers a sustainable approach for the successful utilization of the pollutant soot in the form of waste black carbon (BC), collected from the exhausts of a diesel engine as an efficient adsorbent. The morphology of the as-isolated diesel particulate soot was observed in nanosize consisting of an Onion like Nano-Carbon (ONC) structure. The ONC were transformed into water-soluble Onion like Nano-Carbon (wsONC) via the simplest method of oxidation. For applicability as an adsorbent, wsONC was used for the removal of three cationic organic dyes, methylene blue (MB), crystal violet (CV), and rhodamine B (RhB). Among the three cationic dyes, MB showed significant results compared with the other two. A small amount of wsONC was found to be capable of removing ~100 mg L-1 of MB within the time of ?60 min. While with CV and RhB, the removal efficiency was observed to be ~60 mg L-1 and ~40 mg L-1, respectively. In a comparative adsorption analysis, the performance of wsONC was ~2.5 times higher than the as isolated ONC. Another novelty associated with the present finding is the uses of the treated wastewater for watering the Triticum aestivum (wheat) and Cicer arietinum (gram) plants for the initial 15 days. Compared to the dye water, the treated wastewater plants showed healthy growth.

Nitrogen-sulfur codoped carbon dots (NSCD) were synthesized via a single-step microwave-assisted method having a fluorescence quantum yield of ∼12%. The NSCD has been proven to be nontoxic and utilized as a fluorescent imaging nanoprobe for cancer cells (HeLa cells) under UV and blue light excitation (in vitro environment). In addition to the long-known cell imaging application, these NSCD have been used as a sunlight active photomaterial for the removal of toxic hexavalent chromium as Cr(VI). The experimental results reveal that the sunlight active NSCD shows good potential toward the photocatalytic removal of Cr(VI) ions from the wastewater. For the environment and water purification purpose, three different wastewater samples were tested that are synthetic wastewater (up to 100 ppm), laboratory wastewater, and Cr(VI) ion-spiked industrial wastewater for the photocatalytic removal of Cr(VI). The biocompatible NSCD as a fluorescent imaging probe of cancer cells along with its fruitful utilization in photocatalysis under sunlight (compared to the dark condition) demonstrates the overall sustainability of the presented process.

The impact of pollutant-based onion-like nanocarbons (ONC) on the growth of common gram (Cicer arietinum) plants is being explored here. ONC were isolated from the pollutant diesel soot, which on oxidative treatment gets converted to water-soluble ONC (wsONC), and were used for the growth of gram plants. It was observed that there was improvement in overall growth of the gram plants having wsONC in comparison with the control set of experiments (without wsONC). The important finding associated with the presented work is that wsONC up to a certain concentration (10 ppm) when supplemented to gram plants imparts an improved growth. Afterward, the growth of the plants was noticed to be decreased, which advocates the dose-dependent properties of wsONC on plant growth. The physical presence of the wsONC nanoparticles inside the roots of treated plants has been examined by scanning electron microscopy.

Herein, we report a simpler functionalization of the CNR by the amine (2,2′-(ethylenedioxy)-bis(ethylamine)) (H2NCH2CH2OCH2CH2OCH2CH2NH2 (EDA)) molecules as a surface passivating agent to achieve soluble functionalized carbon nano-rods (f-CNR). The surface-functionalized fluorescent f-CNR exhibited the quantum yield value of ∼16% and were used as a fluorescent probe for the selective detection of the Cr(vi) and Fe(iii) ions in a homogeneous aqueous phase based on fluorescence quenching. In particular, the limits of the detection for both metal ions were obtained to be ∼43 nM for Fe(iii) and ∼11 nM for Cr(vi), which were quite significant in aqueous media. Moreover, the f-CNR showed non-toxicity and was biocompatible with Escherichia coli (E. coli) (ATCC 25922) cells when tested up to 9 mg mL-1.