Survival tactics of an endangered species Withania coagulans (Stocks) Dunal to arid environments.

Withania coagulans is a valuable medicinal plant with high demand, but its wild growth and local usage pose a threat to its natural habitat. This study aims to understand the plant's growth, anatomy, and physiology in different environmental conditions to aid in conservation and re-vegetation efforts. Fifteen differently adapted populations of Withania coagulans were collected from diverse ecological regions, viz., (i) along the roadside, (ii) hilly areas, (iii) barren land, and (iv) wasteland to unravel the adaptive mechanisms that are responsible for their ecological success across heterogenic environments of Punjab, Pakistan. The roadside populations had high values of photosynthetic pigments, total soluble proteins, root endodermis thickness, stem and leaf cortical thickness, and its cell area. The populations growing in hilly areas showed better growth performance such as vigorous growth and biomass production. Additionally, there was enhanced accumulation of organic osmolytes (glycine betaine and proline), chlorophyll content (chl a/b), and enlarged epidermal cells, cortical cells, vascular bundles, metaxylem vessels, and phloem region in roots. In case of stem area, epidermal thickness, cortical thickness, vascular bundle, and pith area showed improved growth. However, the barren land population showed significant increase in carotenoid contents, vascular bundle area, and metaxylem area in roots, and xylem vessels and phloem area in stems and leaves. The wasteland population surpassed the rest of the populations in having greater root dry weight, higher shoot ionic contents, increased root area, thick cortical, and vascular bundle area in roots. Likewise, cortical thickness and its cell area, and pith area in stems, whereas large vascular bundles, phloem region, and high stomatal density were recorded in leaves. Subsequently, natural populations showed the utmost behavior related to tissue organization and physiology in response to varied environmental conditions that would increase the distribution and survival of species.

Applications of maximum matching by using bipolar fuzzy incidence graphs.

The extension of bipolar fuzzy graph is bipolar fuzzy incidence graph (BFIG) which gives the information regarding the effect of vertices on the edges. In this paper, the concept of matching in bipartite BFIG and also for BFIG is introduced. Some results and theorems of fuzzy graphs are also extended in BFIGs. The number of operations in BFIGs such as augmenting paths, matching principal numbers, relation between these principal numbers and maximum matching principal numbers are being investigated which are helpful in the selection of maximum most allied applicants for the job and also to get the maximum outcome with minimum loss (due to any controversial issues among the employees of a company). Some characteristics of maximum matching principal numbers in BFIG are explained which are helpful for solving the vertex and incidence pair fuzzy maximization problems. Lastly, obtained maximum matching principal numbers by using the matching concept to prove its applicability and effectiveness for the applications in bipartite BFIG and also for the BFIG.

Synthesis of efficient light harvesting Cr, N Co-doped TiO2 nanoparticles for enhanced visible light photocatalytic degradation of xanthene dyes; eosin yellow and rose bengal.

To solve the problem of water pollution, using environment friendly and cost effective method in short time is the need of hour. In this work, chromium (Cr) and nitrogen (N) co-doped TiO2 nanoparticles were synthesized and were used for the photocatalytic degradation of dyes under visible light. The synergistic effect of metal and non-metal co-dopants added would result in appropriate reduction of band gap {from 3.2 eV of TiO2 to 2.67 eV}, decrease in recombination rate of charge carriers by trapping electrons and holes, and in better light harvesting capacity. Nanoparticles were synthesized by sol-gel method and characterized using ultraviolet-visible (UV-VIS) spectroscopy, fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), zeta potential, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, field emission scanning electron microscopy (FE-SEM), and RAMAN spectroscopy. Eosin yellow (EY) and rose bengal (RB) were subjected to photocatalytic degradation under solar light to check the photocatalytic activity of the synthesized nanoparticles. Effects of dye concentration, the concentration of nanoparticles, time, and pH were investigated to optimize the parameters. The results obtained were remarkable for 20 ppm EY solution took 10 min using 1 gL-1 NPs at pH 3 and 10 ppm RB solution took 5 min using 0.75 gL-1 NPs at pH 5.78 (original pH) for complete degradation. Kinetics studies were also performed and both dyes followed pseudo-second-order kinetics with R2 values 0.99312 and 0.99712 for EY and RB, respectively. The study of degraded products was conducted using high-performance liquid chromatography (HPLC) hyphenated with electron spray ionization mass spectroscopy (ESI-MS) (LC-MS) and possible degradation pathways were made for both dyes. A reusability test was also performed showing the efficiency of the particles was up to 88% after 3 cycles of use. These notable results can be attributed to the efficient removal of organic pollutants using the proposed dopants in this study.

Task-specific polymeric membranes to achieve high gas-liquid mass transfer.

In the current study, Polyimide (P84)-based polymeric membranes were fabricated and used as spargers in the bubble column reactor (BCR) to get a high gas-liquid mass transfer (GL-MT) rate of oxygen in water. Different polymeric membranes were fabricated by incorporating polyvinyl pyrrolidone (PVP) as a porogen and a Zeolitic Imidazolate Framework (ZIF-8) to induce high porosity and hydrophobicity in the membranes. The GL-MT efficiency of membranes was evaluated by measuring the overall volumetric mass transfer coefficient (kLa) of oxygen in air. The kLa of O2 (in air) was measured by supplying the gas through a fixed membrane surface area of 11.94 cm2 at a fixed gas flow rate of 3L/min under atmospheric pressure. The results revealed that adding porogen and ZIF-8 increased the porosity of the membranes compared to the pure polymeric membranes. In comparison, the ZIF-8 (3 wt%) based membrane showed the highest porosity (80%), hydrophobicity (95° contact angle) and kLa of oxygen in air (241.2 h-1) with 78% saturation in only 60 s. ZIF-8 based membranes showed the potential to increase the amount of dissolved oxygen in BCR by reducing the bubble size, increasing the number of bubbles, and improving the hydrophobicity. The study showed that ZIF-8 based membrane diffusers are expected to produce high GL-MT in microbial syngas fermentation. To the best of our knowledge, this is the first study on the fabrication and application of polymeric membranes for GL-MT applications. Further research should be conducted under real fermentation conditions to assess the practicality of the system to support substrate utilization, microbial growth, and product formation.

Kinetics of Biodiesel Production from Microalgae Using Microbubble Interfacial Technology.

As an alternative to fossil fuels, biodiesel can be a source of clean and environmentally friendly energy source. However, its commercial application is limited by expensive feedstock and the slow nature of the pretreatment step-acid catalysis. The conventional approach to carry out this reaction uses stirred tank reactors. Recently, the lab-scale experiments using microbubble mediated mass transfer technology have demonstrated its potential use at commercial scale. However, all the studies conducted so far have been at a lab scale~100 mL of feedstock. To analyze the feasibility of microbubble technology, a larger pilot scale study is required. In this context, a kinetic study of microbubble technology at an intermediate scale is conducted (3 L of oil). Owing to the target for industrial application of the process, a commercial feedstock (Spirulina), microalgae oil (MO) and a commercial catalyst para-toluene sulfonic acid (PTSA) are used. Experiments to characterize the kinetics space (response surface, RSM) required for up-scaling are designed to develop a robust model. The model is compared with that developed by the gated recurrent unit (GRU) method. The maximum biodiesel conversion of 99.45 ± 1.3% is achieved by using these conditions: the molar ratio of MO to MeOH of 1:23.73 ratio, time of 60 min, and a catalyst loading of 3.3 wt% MO with an MO volume of 3 L. Furthermore, predicted models of RSM and GRU show proper fits to the experimental result. It was found that GRU produced a more accurate and robust model with correlation coefficient R2 = 0.9999 and root-mean-squared error (RSME) = 0.0515 in comparison with RSM model with R2 = 0.9844 and RMSE = 3.0832, respectively. Although RSM and GRU are fully empirical representations, they can be used for reactor up-scaling horizontally with microbubbles if the liquid layer height is held constant while the microbubble injection replicates along the floor of the reactor vessel-maintaining the tessellation pattern of the smaller vessel. This scaling approach maintains the local mixing profile, which is the major uncontrolled variable in conventional stirred tank reactor up-scaling.

Intensification of Biodiesel Processing from Waste Cooking Oil, Exploiting Cooperative Microbubble and Bifunctional Metallic Heterogeneous Catalysis.

Waste resources are an attractive option for economical the production of biodiesel; however, oil derived from waste resource contains free fatty acids (FFA). The concentration of FFAs must be reduced to below 1 wt.% before it can be converted to biodiesel using transesterification. FFAs are converted to fatty acid methyl esters (FAMEs) using acid catalysis, which is the rate-limiting reaction (~4000 times slower than transesterification), with a low conversion as well, in the over biodiesel production process. The study is focused on synthesizing and using a bifunctional catalyst (7% Sr/ZrO2) to carry out esterification and transesterification simultaneously to convert waste cooking oil (WCO) into biodiesel using microbubble-mediated mass transfer technology. The results reveal that a higher conversion of 85% is achieved in 20 min using 7% Sr/ZrO2 for biodiesel production. A comprehensive kinetic model is developed for the conversion of WCO in the presence of a 7% Sr/ZrO2 catalyst. The model indicates that the current reaction is pseudo-first-order, controlled by the vapor-liquid interface, which also indicates the complex role of microbubble interfaces due to the presence of the bifunctional catalyst. The catalyst could be recycled seven times, indicating its high stability during biodiesel production. The heterogeneous bifunctional catalyst is integrated with microbubble-mediated mass transfer technology for the first time. The results are unprecedented; furthermore, this study might be the first to use microbubble interfaces to "host" bifunctional metallic catalysts. The resulting one-step process of esterification and transesterification makes the process less energy-intensive and more cost-efficient, while also reducing process complexity.

Integrating bioremediation of textile wastewater with biodiesel production using microalgae (Chlorella vulgaris).

Microalgae-led wastewater treatment is a promising biorefinery approach to promote environmental and economical sustainability. In this study, Chlorella vulgaris (C. vulgaris) was employed for the bioremediation of textile wastewater (TWW) and biodiesel production. C. vulgaris is cultivated in undiluted and diluted TWW (50%). Cultivation in freshwater containing BG11 medium was set as a control. Results show the highest growth (1.62 ± 0.12 OD680) in diluted TWW followed by BG11 medium (1.56 ± 0.15 OD680) and undiluted TWW (0.89 ± 0.11 OD680). The highest methylene blue decolorization of 99.7% was observed in diluted TWW as compared to 98.5% in undiluted TWW. Morever, COD removal efficiency was also higher (99.7 ± 4.2%) in diluted TWW than BG11 medium (94.4 ± 3.5%) and undiluted TWW (76.3 ± 2.8%). For all treatment, more than 80% nitrogen and phosphorous removal were achieved. Otther than this, fatty acids methyl ester (FAME) yield in diluted TWW was higher (11.07 mg g-1) than the undiluted TWW (9.12 mg L-1). Major FAME were palmitic acid (C16:0) and linolenoic acid (C18:3) which are suitable for biodiesel production. All these results suggest that C. vulgaris can be cultivated in both diluted and undiluted TWW for biodiesel production. However, cultivation in undiluted TWW is more favorable as it displaces the need for freshwater addition in the growth medium.

Integrating adsorption and photocatalysis: A cost effective strategy for textile wastewater treatment using hybrid biochar-TiO2 composite.

TiO2 based photocatalysts are extensively used for textile wastewater treatment as they are ecofriendly, inexpensive, easily available, nontoxic and have higher photostabililty. However, their wider band gap, charge carrier's recombination, and utilization of light absorbance limits their performance. In the present work, a hybrid biochar-TiO2 composite (BCT) has been synthesized by a facile synthesis strategy to overcome these problems. These photocatalysts are characterized using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), UV-vis diffuse reflectance spectra (DRS), and photoluminescence (PL) to evaluate their crystallinity, morphology, functional groups, bandgap energy and charge separation properties, respectively. The photodegradation of simulated textile wastewater is analyzed using hybrid composites. The hybrid biochar-TiO2 composite showed higher charge separation, slow recombination of electron-hole pairs, and enhanced light absorption as compared to control (pure TiO2 and BC alone). 99.20 % photodegradation efficiency of dye-simulated wastewater is achieved employing optimum hybrid composite, while the pure biochar and TiO2 samples exhibits 85.20 % and 42.60 % efficiencies, respectively. The maximum adsorption capacity is obtained for hybrid biochar-TiO2 sample, 74.30 mgg-1 in comparison to biochar (30.40 mgg-1) and pure TiO2 (1.50 mgg-1). The results show that hybrid biochar-TiO2 composites can perform in the target application of organic industrial pollutant removal.

Fluidic oscillator-mediated microbubble generation to provide cost effective mass transfer and mixing efficiency to the wastewater treatment plants.

Aeration is one of the most energy intensive processes in the waste water treatment plants and any improvement in it is likely to enhance the overall efficiency of the overall process. In the current study, a fluidic oscillator has been used to produce microbubbles in the order of 100 µm in diameter by oscillating the inlet gas stream to a pair of membrane diffusers. Volumetric mass transfer coefficient was measured for steady state flow and oscillatory flow in the range of 40-100l/min. The highest improvement of 55% was observed at the flow rates of 60, 90 and 100l/min respectively. Standard oxygen transfer rate and efficiency were also calculated. Both standard oxygen transfer rate and efficiency were found to be considerably higher under oscillatory air flow conditions compared to steady state airflow. The bubble size distributions and bubble densities were measured using an acoustic bubble spectrometer and confirmed production of monodisperse bubbles with approximately 100 µm diameters with fluidic oscillation. The higher number density of microbubbles under oscillatory flow indicated the effect of the fluidic oscillation in microbubble production. Visual observations and dissolved oxygen measurements suggested that the bubble cloud generated by the fluidic oscillator was sufficient enough to provide good mixing and to maintain uniform aerobic conditions. Overall, improved mass transfer coefficients, mixing efficiency and energy efficiency of the novel microbubble generation method could offer significant savings to the water treatment plants as well as reduction in the carbon footprint.