Numrah Nisar

High-performance magnetic chicken bone-based biochar for efficient removal of rhodamine-B dye and tetracycline: competitive sorption analysis

Magnetic chicken bone-based biochar (MCBB) was successfully prepared and efficiently adsorbed rhodamine-B (RB) dye and tetracycline (TC) in multi-component systems. The magnetisation value, surface area, and pHpzc of the MCBB were found to be 66.5 emu/g, 328 m2/g, and 8.3, respectively. RB has higher saturation capacity (96.5 mg/g) and occupies more active sites on MCBB, thus limiting the sorption of TC with lower saturation capacity (63.3 mg/g). Langmuir isotherm suitably describes the sorption process in a single-component system; however, the multi-component system was well fitted to the Sheindorf-Rebhun-Sheintuch model. The selectivity factor values confirmed that MCBB had higher adsorption affinity toward RB than TC. The intraparticle diffusion model played a significant role in the sorption process. The MCBB can be easily desorbed with base-spiked H2O and reused without loss in stability or structural integrity.

Muscilage characterization, biochemical and enzymatic activities of laser irradiated Lagenaria siceraria seedlings

Laser stimulation effect on L. siceraria seed mucilage, biochemicals and enzymatic activities during early growth stages were investigated. The laser density power of 1mW/cm2 for 3 and 5min treatments were performed and various responses i.e., seedlings mucilage, biochemical and enzymatic activities were studied. Laser treatment of L. siceraria seeds enhanced the biochemical as well as the enzymatic activities. TPC (total phenolic contents),TFC (total flavonoids contents), TSS (total soluble sugar), reducing sugar, proline contents, total soluble protein and nitrogen contents were recorded higher in laser treated groups versus control. Mucilage from L. siceraria seed coat was also characterized. The pre-sowing seeds were treated with laser radiation for 3 and 5min. TPC, TFC, proline contents, total soluble protein and nitrogenous compounds contents, ascorbic acid contents were recorded higher at 3min. The laser irradiation effect on TSS, hydrogen peroxide (H2O2), malondialdehyde (MDA) was insignificant versus control. The SOD (superoxide dismutase) and POD (peroxidase), AMY (amylase), CAT (catalase) activities were recorded higher for 5min laser treatment. Results revealed that He-Ne continuous wave-laser pre-sowing seed irradiation affected the seed coat mucilage, biochemical and enzymatic activities positively and this treatment could possibly be used to enhance the L. siceraria productivity. Future study will be focused on growth at later stages and yield characteristics of L. siceraria.

Fungal strains isolation, identification and application for the recovery of Zn(II) ions

Fungal biomass proves to be highly efficient for the treatment of wastewater as well as recovery of metal ions from wastewater. Present investigation was aimed to evaluate the efficiency of indigenous fungal isolates for the sequestration of Zn(II) ions aqueous solution. Among twenty five fungal isolates, Aspergillus oryzae SV/09 (AO SV/09), Aspergillus flavus NA9 (AF NA9) and Paecilomyces formosus DTO 63f4 (PF DTO-63f4) were identified by gene sequencing of ITS regions of the ribosomal DNA (rDNA). The AO SV/09, AF NA9 and PF DTO-63f4 showed promising efficiency for the biosorption of Zn(II) ions. Zn(II) ions adsorption was endothermic in nature and data fitted will to the Freundlich isotherm with correlation coefficients values of 0.99, 0.98 and 0.99 for AO SV/09, AF NA9 and PF DTO-63f4, respectively. Pseudo-second order kinetic model explained well the Zn(II) adsorption kinetic of Zn(II) ions onto biosorbents. The adsorbed Zn(II) ions were desorbed using HCl and 85.5, 75.3, 73.7 (%) Zn(II) ions were recovered from AO SV/09, AF NA9 and PF DTO-63f4 sorbents, respectively. The fungal biosorbents were successfully recycled up to five cycles. Based on sorption, recovery and regeneration, the application of fungal bio-sorbents for the sequestration and recovery of Zn(II) ions is suggested from wastewater and could possibly be extended for the recovery of other heavy metal ions from wastewater.

Detoxification of photo-catalytically treated 2-chlorophenol: optimization through response surface methodology

The present study was conducted to degrade and detoxify 2-chlorophenol (2-CP) under UV irradiation in the presence of titanium dioxide (TiO2) and hydrogen peroxide (H2O2). The treatment efficiency was evaluated on the basis of degradation and cytotoxicity reduction as well as biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total organic carbon (TOC) removal. The process variables such as TiO2, pH, UV irradiation time and H2O2 were optimized. Central composite design in combination with response surface methodology was employed to optimize the process variables. A quadratic model was proposed to predict the treatment efficiency and analysis of variance was used to determine the significance of the variables. The correlation between the experimental and predicted degradation was confirmed by the F and P values (<0.05). The coefficient of determination (R2 = 0.99) were high enough to support the validity of developed model. At optimized conditions, up to 92% degradation of 2-CP was achieved with 3.5 × 10-4 s-1 rate constant. Significant reductions in BOD, COD and TOC values were also achieved. Cytotoxicity was evaluated using bioassays and it was observed that UV/TiO2/H2O2 reduced the cytotoxicity considerably. It is concluded that UV/TiO2/H2O2 could possibly be used to detoxify 2-CP in industrial wastewater.

Reduction of reactive red 241 by oxygen insensitive azoreductase purified from a novel strain Staphylococcus KU898286

An oxygen insensitive azoreductase was purified from a novel bacterial strain (Staphylococcus sp. KU898286) that was isolated from an abandoned site of the textile waste discharge unit. The isolated enzyme had efficiently cleaved the azo-bonds through reductive transformation under aerobic conditions. Initial phenotypic characterization and final construction of phylogenetic tree on the basis of 16s rDNA demonstrated 99% resemblance of the isolate to Staphylococcus aureus. The purified azoreductase was found to have a broad spectrum activity that reduced RR241 at a concentration of 50mg/L with pH between 6–8 and 30°C temperature). Besides, the reactive red 241 (RR241) was reduced at extracellular level as well as NADH dependent intracellular level. Complete reduction/ decolourization of RR241 were achieved after 18 hrs of exposure. The final degradation product observed to be 2-nephthol was purified by High Pressure Liquid Chromatography (HPLC) and the molecular mass was computed by Gas Chromatography-Mass spectroscopy (GC-MS). The study revealed a cost effective and eco-friendly approach to degrade the toxic dyes into less toxic products by Staphylococcus sp. KU898286.

Coal desulfurization using gamma and ultraviolet radiation

ABSTRACT Combustion of coal produces oxides of sulfur that is harmful for the environment. Present research work was aimed to appraise the desulfurization of coal using high-energy radiations. Gamma radiations (γ-rays) and ultraviolet radiations (UV) were employed for the desulfurization of coal under different media conditions. Coal slurries in these media were treated for different time intervals of UV radiation and γ-rays doses (50, 100, 150 kGy). The maximum sulfur removal was achieved up to 54 and 36% by γ-radiation and UV radiation, respectively, which is due to the more ionizing power of γ-rays treatment. To effectively and efficiently remove sulfur from coal, the use of high-energy radiations is suggested for the desulfurization of coal.