The present study focuses on effects of initial pH on dibenzothiophene (DBT) desulfurization via 4S pathway by growing cells of Ralstonia eutropha. For so doing, temporal changes of biomass concentration, glucose as a sole carbon source, pH value, and 2-hydroxybiphenyl (2-HBP) formation have been monitored during the bioprocess. The biomass concentration has been modeled by the logistic equation and results show that the values of maximum specific growth rate (μmax) and maximum cell concentration (Xmax) have increased in line with the rise of initial pH from 6 to 9. This confirms the effect of pH on the energetics of cell growth via altering the proton gradient and manipulating ATP-related metabolic pathways. By considering the Pirt’s maintenance concept, the bioenergetic aspects of DBT desulfurization process are affected by changes in pH, where the maximum specific DBT conversion rate (0.0014 mmol/gcell.h) has been obtained at initial pH of 8. Additionally, the kinetic modeling of the 2-HBP formation through the Luedeking-Piret model indicates that the DBT desulfurization rate is linearly related to the cell growth rate, instead of biomass concentration. The growth associated and non-growth associated 2-HBP formation constants have been obtained 3.82 mg2-HBP/gcell and 0.06 mg2-HBP/gcell.h, respectively at an initial pH of 8.

The present study aims at developing a forecasting model to predict the next year’s air pollution concentrations in the atmosphere of Iran. In this regard, it proposes the use of ARIMA, SVR, and TSVR, as well as hybrid ARIMA-SVR and ARIMA-TSVR models, which combined the autoregressive part of the autoregressive integrated moving average (ARIMA) model with the support vector regression technique (ARIMA-SVR). The main concept of generating a hybrid model is to combine different forecasting techniques so as to reduce the time-series forecasting errors. The data used in this study are annual CO2, CO, NOx, SO2, SO3, and SPM concentrations in Iran. According to the results, the ARIMA-TSVR Model is preferable over the other models, having the lowest error value among them which account for 0.0000076, 0.0000065, and 0.0001 for CO2; 0.0000043, 0.0000012, and 0.000022 for NOx; 0.00032, 0.00028., and 0.0012 for SO2; 0.000021, 0.000014, and 0.00038 for CO; 0.0000088, 0.0000005, and 0.00019 for SPM; and 0.000021, 0.000019, and 0.0044 for SO3. Furthermore, the accuracy of all models are checked in case of all pollutants, through RMSE, MAE, and MAPE value, with the results showing that the hybrid ARIMA-TSVR model has also been the best. Generally, results confirm that ARIMA-TSVR can be used satisfactorily to forecast air pollution concentration. Hence, the ARIMA-TSVR model could be employed as a new reliable and accurate data intelligent approach for the next 35 years’ forecasting.

Management of solid wastes is considered as an economic and environmental issue in the building stone industry. The current study uses raw and calcined calcareous sludge, generated in the stone cutting factories, in order to remove sulfur dioxide. Sludge characterization has been performed, using X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analyses. The removal experiments of sulfur dioxide have conducted under different humid contents and adsorbent doses. The results showed that the higher the adsorbent dosage and humidity content, the greater the SO2 adsorption.. The calcination process at temperatures of 400, 500, 600, and 700℃ revealed that with rising calcination temperature and humidity content, the adsorbent capability is enhanced considerably. This method could be developed for the management of stone sludge produced from the stone cutting industry through its conversion into an effective and low-cost adsorbent for desulfurization process.

In this study, the lethal toxicity, behavioral responses and hematotoxicity of formulated chlorpyrifos on Clarias gariepinus was evaluated. C. gariepinus fingerlings were exposed to 0.2 mg/L, 0.25 mg/L, 0.3 mg/L, 0.35 mg/L and 0.4 mg/L of the active ingredient chlorpyrifos to determine the lethal concentrations and behavioral effects. C. gariepinus juveniles (38.84±7.67g) were then exposed to 0.0256 mg/L and 0.0128 mg/L for 14 days to study somatic indices and haematological effects. The 24h, 48h, 72h and 96h LC50 were estimated as 0.292 (0.210 – 0.376) mg/L, 0.275 (0.252 – 0.297) mg/L, 0.263 (0.242 – 0.282) mg/L, and 0.256 (0.235 – 0.275) mg/L respectively. Hyper activity, loss of equilibrium, erratic swimming, trembling, respiratory distress and poor startle response were observed in fingerlings in response to acute toxic stress of chlorpyrifos. Liver somatic index (LSI) of exposed juveniles increased significantly (p<0.05) compared with control, while there was no statistically significant difference in all the haematological parameters of the exposed fishes compared with the control (p<0.05). The results indicate that the chlorpyrifos formulation was highly toxic and induced behavioral changes in C gariepinus fingerlings, while sub-lethal concentrations induced inflammation in the liver but had no effect on haematological parameters of Clarias gariepinus juveniles. LSI was sensitive to the sub-lethal concentrations and could serve as indicators or exposure to organophosphate insecticides.

Pyrolysis is an applicable method that has been widely used to recover hydrocarbons from Used Lubricating Oil (ULO). However, large-scale application of this approach has been limited by its noticeably energy and time consuming nature. In the present research, it has been attempted to modify the energy and time requirements of ULO pyrolysis using the catalytic effects of metal oxide nanoparticles (NPs). The impacts of γ-Al2O3, γ-Fe2O3 and ZnO NPs on the kinetic features of ULO pyrolysis were studied using thermogravimetric analysis (TGA). The kinetic parameters of the pyrolysis process were calculated based on Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozava (FWO) models. The activation energy of virgin ULO pyrolysis had been calculated to be 161.505 and 162.087 kJ/mol using KAS and FWO models, respectively. However, in the present work, utilization of γ-Fe2O3 NPs significantly reduced the activation energy of ULO pyrolysis to 133.511 and 138.289 kJ/mol through KAS and FWO models, respectively. The catalytic effect of ZnO NPs was not as noticeable as that of γ-Fe2O3 NPs, resulting in activation energies of 155.568 and 158.501 kJ/mol using KAS and FWO models, respectively. Moreover, based on the results of this study, γ-Al2O3 NPs had no significant impact on the kinetics of ULO pyrolysis.

Global plastic production has exceeded 300 million tons per year (Plastics Europe, 2015). In the marine and freshwater environments, larger plastics abrade and photo-degrade resulting in persistent environmental microplastics that are not effectively removed by existing wastewater treatment plants (WWTPs). The ecological effects of microplastics on the marine environment are poorly understood, with even less attention to freshwater systems. To assess whether microplastics have infiltrated food webs of shallow nearshore ecosystems of the St. Lawrence River, we sampled four sites along the international section of the St. Lawrence River, from Alexandria Bay to Waddington, NY. Twelve sediment samples along with one hundred and forty-nine Dreissenid mussels (Dreissena polymorpha and D. bugensis) were collected from the littoral zone, and forty one road-killed anuran amphibian specimens were collected adjacent to the river.  Sediment subsamples at two of four sediment sampling sites contained plastic micro-particles. No microbeads were detected within any of the Dreissenid mussels or anuran digestive tract samples. The Dreissenids were likely too small to ingest microbeads greater than 35 microns. Microplastics congregating in the littoral zone may pose a threat within the food web through potential ingestion, requiring further methodological development.

In the present study, analytical solutions are developed for three-dimensional advection-dispersion equation (ADE) in semi-infinite adsorbing saturated homogeneous porous medium with time dependent dispersion coefficient. It means porosity of the medium is filled with single fluid(water). Dispersion coefficient is considered proportional to seepage velocity while adsorption coefficient inversely proportional to dispersion coefficient. Solutions are derived for both uniform and varying plane input source. The source geometry, including shape and orientation, broadly act major role for the concentration profile through the entire transport procedure. Initially the porous domain is not solute free. It means domain is throughout uniformly polluted. With help of certain transformation advection-dispersion equation is reduced into constant coefficient. The governing advection-dispersion equation, initial and boundary condition is solved by applying Laplace Transform Technique (LTT). The desired closed-form solution for the line source in two-dimensions and point source in one-dimension of uniform and varying nature are also evaluated as particular cases. Effects of parameters and value on the solute transport are demonstrated graphically.

Surface water contains a large number of pollutants, particularly human pathogens, organic toxicants and heavy metals. Due to the toxic nature of heavy metals towards marine organisms, its removal from the environment has been a growing issue. The biosorption of heavy metal ions from surface water using fish scales has emerged as an environmentally friendly technique. This study assessed the degree of heavy metals accumulation in the scales of Oreochromis niloticus and determining its efficiency as a bioindicator for Cu, Mn and Fe ions removal in the environment of Wewe and Owabi rivers. This study shows that the levels of Cu, Mn, Fe adsorbed from the Owabi river were 685.70 ± 16.51, 247.06 ± 50.46 and 892.90 ± 96.29 mg/kg, respectively. Moreover, the levels of Cu, Mn and Fe adsorbed from Wewe river were 501.60 ± 77.78, 300.89 ± 54.61     and 413.04 ± 9.92 mg/kg, respectively. Under best optimum adsorption conditions, Cu was the best removed heavy metal ions in both surface water reservoirs. Multivariate analysis showed that Cu and Mn showed association in Owabi river, while Mn and Fe were correlated in Wewe river signifying their similarities to a common anthropogenic activity. The Fourier–transform infrared spectrum revealed the existence of a nitro, amine, and carbonyl groups in the biosorption process. This study highlighted that Oreochromis niloticus scales was an efficient bio–sorbent in removing Cu, Mn and Fe ions from Owabi and Wewe rivers.

Biomass derived from Tamarindus indica partially activated seed coat was investigated for the removal of nitrate ions from aqueous solutions. Batch experiments were performed to evaluate the parameters like pH, contact time, sorbent dose and initial nitrate concentration. pH of the solution played vital role. The maximum sorption observed at pH=7, sorbent dose 300mg, contact time at 120min, initial nitrate concentration 5mg. Physicochemical properties of the biomass were evaluated using scanning electron microscopy (SEM), energy dispersive X-ray analysis and Fourier Transform infra red (FTIR) spectroscopy. The SEM and FTIR data reveals the suitable surface and the presence of chemical functional groups such as hydroxyl, amide, carbonyl strong acid and primary amine on the biosorbent surface contributes to biosorption. The equilibrium isotherms and kinetics were deliberated. Biosorption equilibrium followed Langmuir isotherm. Pseudo second order kinetics provided better correlation of the experimental data in comparison with pseudo-first-order kinetic model. The study indicated that Tamarindus indica partially activated seed coat biomass found to be a novel biosorbent for the removal of nitrates from aqueous solutions.

This study carried out to investigate the production of hydrogen using the organic fraction of municipal solid waste OFMSW, where the anaerobic digester was depended as a method for disposing and treating OFMSW and producing bio-hydrogen. Bio-hydrogen production had been studied under different parameters including pH, solid content T.S%, temperature and mixing ratios between the thick sludge to OFMSW. The optimal conditions were found at pH, T.S%, temp and mix ratio of 7, 8%, 32oC, and 1:5, respectively where the hydrogen yield was (138.88 mL/gm vs).  To found the most important parameters in this process, the ANN model had been applied. The effectiveness of temperature, total solid, mixing ratio and pH comes in the following sequence 100%, 75.8%, 71.9%, and 57.2% respectively, with R2 of 95.7%. Multiple correlation model was used to formulate an equation linked between the hydrogen production and the parameters effected on. Gompertz model was applied to compare between theoretical and experimental outcomes, it also given a mathematical equation with high correlation coefficient R2 of 99.95% where the theoretical bio-hydrogen was (141.76 mL/gm vs) under best conditions. The first order kinetic model was applied to evaluate the dynamics of the degradation process. The obtained negative value of (k = - 0.0886), indicates that, the solid waste biodegradation was fast and progresses in the right direction.