Search

AbstractThe rise in cyanide concentration in groundwater in many developing countries is linked to the indiscriminate discharge of cyanide-bearing wastewater from cassava processing industries. This research synthesized a super-active activated carbon (AC) from a novel biomass precursor, Raphia hookeri kernel, functionalized with phosphoric acid via in-situ and ex-situ methods. Morphological and functional characterizations were performed, and the influence of some key process variables on cyanide adsorption was also investigated for the two derived ACs to study the impact of the activation method used. The optimal conditions for cyanide adsorption for the in-situ and ex-situ–derived ACs were identified as pH 8, AC dose of 0.15 g, temperature of 40 °C, and initial cyanide concentration of 100 mgL−1 at different equilibrium times of 100 min and 120 min, respectively. The kinetic studies revealed that the pseudo-second-order kinetic model fitted the adsorption data better for the two ACs based on the high correlation coefficients (r2), suggesting that the adsorption process is chemisorption. The equilibrium studies showed that the in-situ-derived AC followed the Langmuir isotherm with a maximum adsorption capacity (qm) of 93.821 mgg−1 indicating monolayer adsorption for the in-situ-derived AC. The ex-situ-derived AC, however, followed the Sips isotherm with a maximum adsorption capacity (qm) of 79.381 mgg−1 indicating a heterogeneous surface for the ex-situ-derived AC. The ACs showed decreasing cyanide adsorption after five cycles but maintained significant adsorption capacity after desorption-adsorption cycles. [ABSTRACT FROM AUTHOR]

A new distribution for modeling the two approaches (physical and actuarial) of reliability problems is introduced. The statistical properties including the moments, mode, quantile function are derived. Some reliability measures including the mean residual life and hazard rate are derived. An alternative measure for total time of test (TTT) for evaluation of the interfailure times is drived. The unknown parameters of the new distribution are estimated using the maximum likelihood approach. Furthermore, the asymptotic consistency of the estimated parameters is evaluated through a simulation study. Two real-life datasets were used to illustrate the applicability of the new distribution and comparison with already existing distributions. [ABSTRACT FROM AUTHOR]

Furfural contamination of water is a serious problem in the world. The review article highlights on furfural ecotoxicology and the associated molecular mechanisms involved in its toxicity, efficacy of novel adsorbents for the removal of furfural from polluted water, adsorption capacities of adsorbents under different conditions, such as surface area, concentration, adsorption capacity, pH, time, temperature, applicable isotherm models, characterization and percentage removal of furfural. It was showed from the review that CTAB-bentonite is the best adsorbents for the removal of furfural (q max = 538 mg/g) from aqueous media.A wide range of values for the thermodynamic parameters (both negative and positive) were reported for furfural across different studies. Furfural uptake best-fit both for the Langmuir and Freundlich isotherm models as well as a pseudo second order kinetic model. Additionally, the review also highlighted the molecular modelling and simulations of furfural adsorptions and detail about its future prospects. Among the different treatment options, advanced oxidation processes (AOPs) are likely promising for efficient degradation of furfural in water and wastewater. [Display omitted] • Ecotoxicology effects of furfural. • Adsorption and Advanced oxidation processes (AOPs) removal of furfural from industrial effluents. • Empirical results on equilibrium isotherms, kinetics and thermodynamics. • Molecular modelling and simulation of furfural adsorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aniline as a toxic aromatic uptake from industrial effluents was reviewed. • The different empirical findings on the equilibrium isotherms, kinetics and thermodynamics. • Molecular modelling and simulation of aniline adsorption. • Azo-linked porous organic polymer is the best adsorbents for the removal of aniline. • The best fit kinetic model for aniline adsorption is the pseudo-second-order model. This review aims to report the efficiency of the adsorption of industrial pollutants, aniline, from wastewater. It was observed from the review that an Azo-linked porous organic polymer (AZO-POP-1) is the best adsorbents for the removal of aniline from aqueous media, with a capacity adsorption (q max) of 1059 mg/g. In terms of factors that affect the efficiency of adsorbents, temperature seems to be the most influential. Aniline uptake best-fit both the Langmuir and Freundlich isotherm models as well as a pseudo second order kinetic model. Different potential adsorbents have been examined through simulations, usually using density functional theory (DFT) or ab-initio method. Most of the time they are simulated in the gas phase, but for a realistic adsorption model, they should be simulated in the solvent phase. Although some studies have been reported on molecular modeling of aniline adsorption using a different range of computational approaches, there are still a lot of issues to be addressed. These issues include the solvent effects which are not properly modeled, the calculation of adsorption energy which is not taking the environment into account, and possibly the temperature effects. [ABSTRACT FROM AUTHOR]