Photocatalytic degradation of reactive dyes using natural photo-smart pigment-A novel approach for waste water re-usability.

The present study is aimed at an efficient photocatalytic degradation of industrially important reactive dyes using phycocyanin extract as a photocatalyst. The percentage of dye degradation was evidenced by a UV-visible spectrophotometer and FT-IR analysis. The degraded water was checked for its complete degradation by varying pH from 3 to 12. Furthermore, the degraded water was also analyzed for water quality parameters and was found to meet industrial wastewater standards. The calculated irrigation parameters like magnesium hazard ratio, soluble sodium percentage, and Kelly's ratio of degraded water were within the permissible limits, which enables its reusability in irrigation, aquaculture, as industrial coolants, and domestic applications. The calculated correlation matrix shows that the metal influences various macro-, micro-, and non-essential elements. These results suggest that the non-essential element lead can be effectively reduced by increasing all the other micronutrients and macronutrients under study except sodium metal.

Spirulina carbon dots: a promising biomaterial for photocatalytic textile industry Reactive Red M8B dye degradation.

The colorful reactive dyes are toxic, carcinogenic to living organisms and pollute the water environment. We, for the first time, have studied the lab-scale synthesis of novel and eco-friendly carbon quantum dots (CQDs) from Spirulina platensis by microwave-assisted technology. Fluorescence, absorbance, emission, and excitation spectra of biosynthesized CQDs were recorded by UV transilluminator, UV, and photoluminescence spectrophotometer. Elemental analysis of CQDs were carried out by using energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Morphological properties of CQDs were studied by using transmission electron microscope (TEM), scanning electron microscope (SEM), and particle size analyzer. Up to 95.5% of Reactive Red M8B was degraded by CQDs within 6 h under sunlight. Dye degradation was facilitated by optimized parameters such as concentration of dyes, catalyst, and pH. Photocatalytic activity of CQDs were studied by gas chromatography mass spectrometry (GC/MS). It proved that the complex molecules were degraded to simpler and easily degradable molecules. Dye degradation reaction follows first-order kinetics, and the synthesized CQDs contain 89% of scavenging activity. MTT assay proved that the treated water was toxic free and charcoal was used to remove the CQDs from treated water in order to standardize the permitted level of physico-chemical parameters such as biological oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), and total inorganic carbon (TIC); chemical, metal, and toxic-free dye treated water was suitable to recycle for algae cultivation.

Optimization of reduced Graphene oxide synthesis using central composite design analysis-A waste to value approach.

In recent times, reduced graphene oxide has gained more attention in various fields. In our study, a direct synthesis of reduced graphene oxide using a novel carbon-rich agro-waste from Pennisetum glaucum was used. Ferrocene acted as an oxidizing agent during thermal degradation at 300 °C for 15 and 20 min to promote graphene oxide and reduced graphene oxide formation. The X-ray diffraction peak at 2θ indicating a shift from 16.86 to 24.28°, presence of functional groups like -OH stretching, -C = C-, C = O, C-O, and C-OH by Fourier transmission infrared spectroscopy, prominent D and G bands at 1308 cm-1 and 1578 cm-1 by Raman spectra and UV-visible spectroscopy peak shift from 235 to 245 nm (π-π*, C = C bonds) confirmed the reduction of graphene oxide to reduced graphene oxide. The average particle size values 233.3 nm for graphene oxide and 63.57 nm for reduced graphene oxide illustrate the nanoscale range of our synthesized material. The negative zeta potential values in the range - 45.5 mV and - 29.5 mV for graphene oxide and its reduced forms infer the dispersion stability along with surface oxygen group presence. We have also highlighted the formation of graphene oxide quantum dots by magnetic stirring and confirmed by UV transilluminator and photoluminescence spectra. The photodegradation efficiency was optimized using central composite design for dosage, dye concentration, pH, and time for both malachite green and reactive blue dye. The kinetic studies report pseudo-first-order kinetic model for catalytic degradation and statistical Analysis of variance proved the significance of the process for p value < 0.05. Thus, the synthesized graphene materials could be used as a potential candidate for environmental applications.

Phycocyanin from Spirulina platensis bio-mimics quantum dots photocatalytic activity: A novel approach for dye degradation.

In our present study, the photocatalytic degradation of malachite green (MG) an organic dye was carried out using a phycocyanin extract of Spirulina platensis under the irradiation of sunlight. The aim of the present study is to incorporate a simple, novel, an eco-friendly, and cost-effective degradation of dyes without using any harmful metals and chemicals. It was observed that 25 ppm of MG dye got degraded nearly to 100 % at 3 h. The UV absorbance studies indicate the absence of a peak at 620 nm which is a conclusive evidence for MG dye degradation. An optimization study of MG dye degradation was evaluated by Response Surface Methodology using Minitab module 20.4.0.0 statistical software and its percentage of degradation was statistically analyzed using analystat. The FT-IR studies of raw spectra show minimal variation; however, the deconvoluted spectra in the region of 1600-1700 cm-1 indicate the variation in the secondary structure of amide I bands that leads to the dye degradation. The dye degradation study mainly follows the first-order kinetics between the time intervals of 60-180 min. The characteristics of degraded water were assessed by a TOC analyzer. The value of total inorganic carbon (TIC) in MG before treatment was 90 mg/L and seems to be slightly high when compared to MG after treatment which was found to be 87.65 mg/L and the adsorbent-treated water with a low value of 54.25 mg/L. These results well matched with the characteristics of normal water. The presence of phycocyanin in the degraded water was effectively removed by treating with activated carbon and it was confirmed with fluorescence analysis. These results support that the MG dye degradation was exhibited by phycocyanin extract and bio-mimics the quantum dot photocatalytic activity.

Morphological Modification of Carbon Nanoparticles after Interacting with Methotrexate as a Potential Anticancer Agent.

PURPOSE: Production of highly penetrable and targetable drug delivery particles is mainly focused by current therapy and such focus is achieved in our present study. The carbon nanoparticle (CNP) prepared from purely natural source was modified from spherical shape to cylindrical floral like structure after treatment with the anticancer drug methotrexate (CM). METHODS: The physiochemical properties of the CNP and CM was characterized using FT-IR/Raman Spectrometer, XRD, SEM, AFM, particle size analyzer and its biological evaluation using haemolysis and MTT assay. RESULTS: The shift in FT-IR peaks at 1592, 1120 cm-1 and peaks of raman spectra observed at 1303, 1300 cm-1 represents ordered carbon nanotubes. The morphological change from spherical to cylindrical floral like structure was observed using SEM and AFM and its particle size distribution analysis shows an average diameter of 269 nm for CM. XRD peak at 2θ = 23.86° (002) indicates the presence of large amount of amorphous material that corresponds to multi-walled carbon nanotubes. Haemocompatibility studies proved the safety level usage as 100 µg/ml and MTT assay shows viability rate of 85-98% with mouse embryonic fibroblast (NIH/3 T3) and 30-45% with pancreatic carcinoma (MIA PaCa-2) and gastric cancer cell lines (SNU- 484) respectively.These results are also supported by phase contrast microscope images observed after staining with calcein AM and EthD-1. CONCLUSIONS: The morphologically modified CNPs has shown good anticancer, biocompatibility and haemocompatibility property which is an important criterion to be satisfied by a biomedical product.