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Drought is one of the major abiotic stresses which negatively affects plant growth and development. The current study evaluated the effects of drought on the growth, physiology, and biochemical attributes of wheat seedlings; and examined the role of foliar application of ZnO nanoparticles in alleviating drought-induced effects. Two wheat cultivars i.e., Anaj-2017 and FSD-2018 were grown in soil-filled pots and were subjected to 100% field capacity (FC) (well watered) and 50% of FC (drought stress). Whilst different treatments of ZnO nanoparticles spray included no spray, water spray, and 50, 100, and 150 ppm ZnO. Results demonstrated that drought caused a significant reduction in seedling fresh and dry weights, photosynthetic pigmentation, and antioxidant activities compared with a well-watered treatment. Nevertheless, the application of 100 and 150 ppm of ZnO nanoparticles effectively ameliorated the negative effects of drought and enhanced the performance of both cultivars under drought. Data revealed a significant increase in fresh and dry weight of shoot and root with the application of ZnO nanoparticles. A substantial increase of 73.68% and 28.51% in chlorophyll "a" and 26.15% and 50.02% in chlorophyll "b" was recorded with the application of 100 ppm of ZnO nanoparticles in Anaj-2017 and FSD-2018, respectively over control (0 ppm). The application of these nanoparticles also triggered the antioxidant defense system and protected the crop from oxidative damage. Averaged across different stress treatments, application of 150 and 100 ppm of ZnO nanoparticles increased the peroxidase activity by 60% and 72% in FSD-2018, and 15% and 23% in Anaj-2017, respectively compared with no spray. FSD-2018 outperformed Anaj-2017 regarding its overall performance under ZnO treatments and drought conditions. In a nutshell, it can be concluded that ZnO nanoparticles ameliorated the negative impacts of drought by improving the growth, physiology, and antioxidant defense of both wheat cultivars. • Drought reduced seedling growth, photosynthetic pigmentation, and antioxidant activities. • ZnO NPS efficiently improved growth, and photosynthetic pigments. • ZnO NPs triggered antioxidant defense system for lowering oxidative stress. • FSD-2018 outperformed Anaj-2017 regarding its overall performance under drought conditions. [ABSTRACT FROM AUTHOR]

Clay-based composites were prepared, characterized, and applied for the elimination of Blue FBN (BFBN) and Rose FRN (RFRN) dyes. The Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Thermogravimetric (TGA) and X-ray diffraction analyses were performed to check the interaction of dye molecule with adsorbents. The analysis showed a successful interaction between adsorbent and dyes ions. The experimental data was best fitted with Freundlich isotherm for both dyes (BFBN and RFRN). The findings revealed that at 80 min the adsorption grasped equilibrium in the case of both dyes and succeeded the pseudo-second-order kinetics model. Furthermore, the enthalpy (ΔH°), Gibbs free energy (ΔG°) and entropy (ΔS°) changes suggested that adsorption was exothermic, physical and spontaneous in nature. The maximum adsorption capacities were determined as 76.39% for BFBN and 59.85% for RFRN dye at pH 2.0 and 30 °C. Composites found to be stable at higher temperature and regenerated using MgSO 4 eluting agent. The textile effluent colour was removed up to 50.35 and 54.95% using raw and modified clay, respectively. The modified clay showed promising efficiency for adsorption of synthetic BFBN and RFRN dyes from aqueous solution, which could be a viable option for the treatment of industrial wastewater and textile effluents. • Clay based adsorbents prepared and applied for the adsorption of dyes. • Adsorbents were characterized by FTIR, SEM, TGA and XRD techniques. • Isotherms and kinetic models were applied to evaluate the adsorption nature. • Adsorption capacity of acidified clay was higher versus raw clay. • Acidified clay has potential to treat wastewater contains dyes. [ABSTRACT FROM AUTHOR]

This study focuses on the investigation of adsorptive behavior of Cu, Ni, and Zn ions by Archontophoenix alexandrae in single metal system (SMS), bi-metal system (BMS), and tri-metal system (TMS). This was done through a novel strategy by combining factorial design (FD), response surface methodology (RSM), and mixture design (MD). The adsorption study was carried out as a function of pH, contact time, and biomass dosage and validated through screening design. To improve adsorption capacities of metallic ions, RSM and MD involving central composite design and simplex lattice design were used. The experimental designs demonstrated the maximum adsorption capacity for Cu. The existence of Cu ions suppressed the adsorption of Ni and Zn ions. Langmuir isotherm model and the pseudo-second-order kinetic model best explain the adsorption kinetics of Cu(II), Ni(II), and Zn(II) metal ions on to A. alexandrae. The A. alexandrae could possibly be used as an efficient biosorbent for the removal of toxic pollutants from industrial effluents. [ABSTRACT FROM AUTHOR]

Cellulose/clay composites were prepared and applied for the adsorption of Drimarine Yellow HF-3GL direct dye. The prepared composites were characterized by FTIR, TGA, EDX, SEM and XRD techniques. Bagasse was used as a cellulose source, while clay was obtained from local source, which was modified chemically before composite preparation. Adsorption efficiencies were compared of composite I and II as a function of contact time, temperature, pH, initial dye concentration and composite dose. Non-linear kinetic and equilibrium isotherm employed and dye adsorption data fitted well to pseudo-second order kinetics model. Among isotherms, the Redlich-Peterson isotherm well defined the sorption process of dye on to composites. Thermodynamic factors (ΔS°, ΔH° and ΔG°) revealed that the sorption process was spontaneous, exothermic and feasible. Cellulose/clay composite I and II removed 88.64% and 89.95% dye with 60 min at pH 2 and 30 °C, respectively. For reusability, desorption was performed using different eluting agents and NaOH showed higher desorption efficiency. For the treatment of wastewater, the developed composites were applied to textile effluents and color removal of (90–96.07%) and (97–98.23%) was achieved using cellulose/clay composite I and II, respectively. The results showed that cellulose/clay composite are efficient for the removal dyes and could possibly be used for the treatment of textile effluents. • Cellulose biocomposites were prepared with clay. • Composites were characterized by FTIR, TGA, EDX, SEM and XRD techniques. • Process variables were optimized for the removal of Drimarine Yellow HF-3GL dye. • Kinetics, isotherms and thermodynamics were applied to evaluate the adsorption nature. • The biocomposites showed promising efficiency for textile wastewater treatment. [ABSTRACT FROM AUTHOR]

The current study indicates the sequestering of uranium (VI) onto eucalyptus bark. The batch-scale removal of uranium (VI) onto eucalyptus bark has been investigated with various parameters, such as contact times, pH, biosorbent dose, temperatures and initial uranium (VI) concentrations. Value ofR2and six non-linear regression error functions, namely hybrid fractional error function, Marquardt’s percent standard deviation, average relative error, sum of the errors squared, sum of the absolute errors and Chi-square test (χ2), are considered as tools to predict the most optimum kinetic and isothermal models. The experimental results fitted well to the pseudo-second-order kinetic and Langmuir isothermal models. Maximum sorption capacity (48.99 mg/g) of eucalyptus bark was observed at optimum conditions (pH 6, contact time of 80 min, 0.05-g/L biosorbent dose, 35°C temperatures and initial uranium (VI) concentration of 90 mg/L). The thermodynamics of uranium (VI) ions sorption onto eucalyptus bark indicates the spontaneous and exothermic nature of the process. The competitive biosorption of Zn(II), Cd(II), Cr(III) and Pb(II) with uranium was studied and results depicted that Cr3+had the most inhibitory effect, while Pb2+had the least inhibitory effect on uranium biosorption. Decrease in peak sharpness in the loaded sample compared to native supports the involvement of functional groups in the sorption process. The results of the study prove that eucalyptus bark is a very useful and economical biosorbent for the removal of uranium (VI) from aqueous solutions. [ABSTRACT FROM AUTHOR]

The biocomposites of polypyrrole (PPY), polyaniline (PANI) and sodium alginate (NaAlg) with cellulosic biomass barley husk (BH) were prepared and employed for the removal of 2,4-dichlorophenol (2,4-DCP) form aqueous media. The sorption of 2,4-DCP was studied using native and biocomposites (PPY/BH, PANI/BH and NaAlg/BH) as function of various process variables. The maximum sorption (q e , 7.55–24.57 mg/g) of 2,4-DCP was achieved in the range of 7–10 pH, 0.05 g composite dose, 25 mg/L initial concentration of 2,4-DCP and 120 min contact time at 30 °C. The FTIR analysis revealed the involvement of amino, hydroxyl and carboxylic groups for the binding of 2,4-DCP on the surface of biocomposites. The Freundlich and pseudo second order kinetics models best explained the 2,4-DCP adsorption on to the biocomposites. The ∆G, ∆H and ∆S parameters were also computed, which revealed the favorable and exothermic adsorption nature of 2,4-DCP. Presence of salts affected the 2,4-DCP adsorption negatively. HCl found to be efficient desorbing agent for 2,4-DCP from composites and up to 65.12% was eluted using 0.5 N solution. In view of promising efficiency, the biocomposites have potential to remove 2,4-DCP form industrial effluents. Unlabelled Image • Biocomposites of polypyrole, polyaniline and sodium alginate with cellulosic biomass were prepared. • Adsorption, kinetics and thermodynamic studies were performed for the removal of 2,4-DCP. • Process variables were optimized along with characterization of biocomposites. • Biocomposites showed promising efficiency and have potential to remove 2,4-DCP from effluents. [ABSTRACT FROM AUTHOR]

The use of empirical models in the research is a vital part of the inventions and investigations of civil and environmental engineering organizations. Linear regression is the most commonly used method for optimization and parameter estimation of different equilibrium and kinetic models for sorption. In addition, the usage of this analysis can be extended to a range of nonlinear error functions, subsequently in consent to broader mathematical approach to parameter estimation. The sorption behavior of U(VI) ions from aqueous solution was studied with untreated, treated, and immobilized rice husk by conducting batchmode sorption experiments. The equilibrium experimental data were fitted to the Freundlich, Langmuir and Redlich-Peterson isotherms by linear and nonlinear regression methods. Kinetic modeling of U(VI) ions removal was also done using linear and nonlinear pseudo-first and second-order rate expressions. In the case of nonlinear regression method, six error functions, namely hybrid fractional error function, Marquardt's percent standard deviation, average relative error, sum of the errors squared, sum of the absolute errors, and Chi-square test were used to predict the parameters involved in the two- and three-parameter isotherms, and also to predict the optimum isotherm. The results showed that nonlinear method could be a better way to obtain the parameters and get the most suitable fitted model for equilibrium and kinetic studies. [ABSTRACT FROM AUTHOR]

• Salinity in arable land is becoming major issue in world. • Foliar application of MLE ameliorated effects of salinity. • MLE in stressed plants c enhanced POD,SOD, GB and TSS. • MLE revealed potential as biostimulant for plants. We evaluated role of exogenous application of moringa leaf extract (MLE) in ameliorating perturbations caused by salinity (200 mM) in some physiological, biochemical and anatomical parameters of two canola varieties i.e. Super (V 1) and Punjab (V 2). Data analysis revealed significant interaction between salinity and plant attributes while MLE ameliorated effects of salinity. Both varieties exhibited an increase in shoot fresh (57%, 53%) and dry weights (37%, 19%) respectively after foliar application of MLE under salinity. In V1, particularly, this incremented growth corresponded to increase in Chl-a (33.53%), Chl-b (36.79%) under foliar application of MLE. The results presented that post MLE application in stressed plants caused comparative enhancement in H 2 O 2 , MDA, GB and TSS in both varieties but in V 1 it was particularly high (27%, 46%, 12%, 13%, respectively) when compared over control. On the other hand, TFAA (31.22%), proline (83.12%), proteins (106%), POD (81.17%), catalase (27.45%), H 2 O 2 (25.47%) and ascorbic acid (74.27%) were also boosted after MLE application in comparison with control. MLE caused a significant enhancement in leaf and stem anatomical characteristics in both varieties compared to control. Although increase was observed after MLE application but V 1 responded more strongly than V 2. Differential behavior of both varieties to MLE revealed potential of it as biostimulant for plants facing salinity. Overall, variance in photosynthetic pigments, osmoprotectants, antioxidants and changes in anatomical characteristics of leaf and stem due to MLE in V 1 and V 2 contributed in salinity tolerance. [ABSTRACT FROM AUTHOR]

The pristine and Ni doped BaNi x Fe 12-x O 19 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) NPs have been fabricated via facile microemulsion approach and the impact of dopants was explored based dielectric, optical, structural and the photocatalytic properties of BaNi x Fe 12-x O 19 nanoparticles. X-ray diffraction and Raman study confirmed the formation of regular hexagonal geometry with space group P6 3 /mmc with crystallite size in 32–50 nm range. Functional groups were identified using FTIR analysis. The remanence (Pr), saturation polarization (Ps) and coercivity (Hc) was explored by P-E loop analysis and the value of Pr and Ps was enhanced with the concentration of dopant. According to PL spectra, highly doped materials had a higher charge separation (e−- h+) and low recombination rate, which resulted in higher photocatalytic degradation activity of fabricated nanomaterials. The optical band gap was found to be 1.78 eV versus undoped (2.60 eV for pristine BaFe 12 O 19). Due to polarizations, the dielectric loss, dielectric constant and tangent loss values were declined, while AC conductivity was enhanced. Photocatalytic performance of doped and undoped samples under visible right irradiation was studied for crystal violet dye. For 100 min exposure to visible light, the highly doped catalyst exhibits 97% degradation versus 60% in case of pristine this is attributed to efficient electron-hole pair separation. Furthermore, quenching effect of different scavengers indicated that hydroxyl radical had a main role, and e− or h+ played a minimal role in CV dye degradation. The enhanced properties due to doping make BaNi x Fe 12-x O 19 a potential candidate for photocatalytic applications under visible light irradiation. [ABSTRACT FROM AUTHOR]

In research of low cost adsorbents for the adsorption of radioactive nuclide, citrus peel waste biomass (CPWB) was studied for the adsorption of zirconium (Zr) ions from aqueous medium. Various process variables were investigated for Zr(IV) adsorption and 3.5, 0.05 g, 40 min, 30° C and 90 mg/L pH, biosobent dose, contact time, temperature and initial Zr(IV) ions concentration, respectively were found out to be best for Zr(IV) adsorption. At optimized conditions, 42.02 mg/g Zr(IV) was adsorbed onto CPWB. Pseudo-second-order kinetic model and Langmuir isotherm model described the Zr(IV) adsorption on to CPWB well. Thermodynamic study showed that the biosorption of Zr(IV) ions onto CPWB was feasible, spontaneous at room temperature and exothermic in nature. FTIR analysis revealed the involvement of carbonyl, hydroxyl and amino functional group in the adsorption of Zr(IV) ions onto CPWA. In view of efficient adsorption of Zr(IV) ions, CPWB is a potential candidates for the adsorption of radioactive nuclide from waste. [ABSTRACT FROM AUTHOR]

In view of promising adsorption efficiency of biocomposites, the removal of imidacloprid was studied using biocomposites of polypyrole (PPY), polyaniline (PAN) and sodium alginate (Na-Alginate) with peanut husk (PH). The affecting variables such as pH, insecticide concentration, composite dose, contact time, temperature were optimized for efficient removal of imidacloprid. The biocomposites showed promising efficiency for the removal of imidacloprid. Among all composites polypyrole composite exhibited maximum efficiency at pH 3, 0.05 g adsorbent dose, 90 min contact time, 25 mg/L initial concentration at 35 °C. Langmuir, Freundlich, Harkins-Jura and Temkin isotherms models were applied on the experimental data. The best fitted were Langmuir and Freundlich isotherms with R2 value > 0.904 and >0.97, respectively. Insecticide adsorption followed the pseudo first order kinetics model. Thermodynamics (free energy, enthalpy and entropy) study revealed that the insecticide adsorption process on to biocomposites was spontaneous and exothermic in nature. This study revealed that the polypyrole, polyaniline and sodium alginate composites with peanut husk have promising adsorption potential and this class of adsorbent could be used for the remediation of wastewater contains imidacloprid insecticide. [ABSTRACT FROM AUTHOR]

Citrus limon peroxidase mediated decolourization of Direct Yellow 4 (DY4) was investigated. The process variables (pH, temperature, incubation time, enzyme dose, H 2 O 2 amount, dye concentration, co-metal ions and surfactants) were optimized for maximum degradation of dye. Maximum dye decolourization of 89.47% was achieved at pH 5.0, temperature 50 °C, enzyme dose 24 U/mL, H 2 O 2 concentration 0.25 mM and DY4 concentration 18.75 mg/L and incubation time 10 min. The co-metal ions and surfactants did not affect the dye decolourization significantly. Response surface analysis revealed that predicted values were in agreement with experimentally determined responses. The degradation products were identified by UPLC/MS analysis and degradation pathway was proposed. Besides, phytotoxicity assay revealed a considerable detoxification in response of biodegradation of DY4 dye. C . limon showed promising efficiency for DY4 degradation and could possibly be used for the remediation of textile effluents. [ABSTRACT FROM AUTHOR]

Climate change and global warming have increased the frequency of extreme heat stress events that severely affect plant production. Photosynthesis is an intricate heat-sensitive physiological process. Heat stress affects CO 2 assimilation, photochemical reactions, D1 and D2 protein turnover, and chlorophyll biosynthesis. Heat stress-induced damage to chloroplast downregulates important chloroplast components and inactivates heat-sensitive proteins, including RuBisCo activase, causing redox imbalance, reducing photosynthetic efficiency, and possibly causing cell death. As all photochemical processes in the Calvin cycle in the stroma and thylakoid lamellae of the chloroplast are prone to heat stress injury, these organelles are the primary activators of cellular heat stress responses and signaling. This review describes approaches to protect crop plants against heat-induced photochemical damage and discusses chloroplast responses, sensitivity, and retrograde signaling that contribute to the sensitivity and tolerance of photosynthetic apparatus. • Plant photosynthesis is an intricate heat-sensitive physiological process. • Heat stress affects chlorophyll biosynthesis, CO 2 assimilation, and D1 and D2 protein turnover. • Heat stress downregulates chloroplast components and inactivates heat-sensitive proteins. • Heat stress causes redox imbalance and reduces photosynthetic efficiency. [ABSTRACT FROM AUTHOR]