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The controversy related to the environment pollution is increasing in human life and in the eco-system. Especially, the water pollution is growing rapidly due to the wastewater discharge from the industries. The only way to find the new water resource is the reuse of treated wastewater. Several remediation technologies are available which provides a convenience to reuse the reclaimed wastewater. Heavy metals like Zn, Cu, Pb, Ni, Cd, Hg, etc. contributes various environmental problems based on their toxicity. These toxic metals are exposed to human and environment, the accumulation of ions takes place which causes serious health and environmental hazards. Hence, it is a major concern in the environment. Due to this concern, the significance of developing technology for removing heavy metals has been increased. This paper contributes the outline of new literature with two objectives. First, it provides the sketch about treatment technologies followed by their heavy metal capture capacity from industrial effluent. The treatment performance, their remediation capacity and probable environmental and health impacts were deliberated in this review article. Conclusively, this review paper furnishes the information about the important methods incorporated in lab scale studies which are required to identify the feasible and convenient wastewater treatment. Moreover, attempts have been made to confer the emphasis on sequestration of heavy metals from industrial effluent and establish the scientific background for reducing the discharge of heavy metals into the environment. [ABSTRACT FROM AUTHOR]

In this present study, tin (Sn) doped MnFe 2 O 4 (Sn 0.15 Mn 0.85 Fe 2 O 4) nanocomposites were synthesized using a microwave combustion method by employing Alocasia odutra plant extract as a natural fuel. Sn is well incorporated with spinel ferrite (MnFe 2 O 4) which is confirmed by XRD analysis. FE-SEM analysis indicates that the synthesized sample having a rod-like structure in nature. The emerging pharmaceutical contaminant, namely, diclofenac (2-(2-(2,6-dichlorophenylamino)phenyl) acetic acid) (DCF), the non-steroidal anti-inflammatory drug was utilized as a model pollutant to evaluate the catalytic efficiency of the Sn 0.15 Mn 0.85 Fe 2 O 4 (SMF) under solar irradiation. SMF shows higher catalytic activity than pristine MnFe 2 O 4 due to a reduction in the bandgap energy from 1.78 eV to 1.54 eV as a result of Sn doping into MnFe 2 O 4. The degradation efficiency of DCF using the SMF catalyst was found to be 99% in a shorter interval (50 min) with 71% mineralization. Radical trapping experiments indicate that the photo-generated holes and hydroxyl radicals actively participate in the degradation process of DCF using the SMF catalyst. The optimum pH for the removal of DCF using the SMF catalyst was found to be 4 with the catalyst dosage of 0.8 g/L. The recycling experiment shows that the SMF catalyst has high stability up to five cycles and low iron leaching ability under optimum conditions. Sn 0.15 Mn 0.85 Fe 2 O 4 catalyst can be recovered using an external magnet from the reaction mixture and it is recycled. It was concluded that the synthesized catalyst can be used as a tertiary treatment option for the removal of emerging pharmaceutical pollutants. ga1 • SMF nanoparticles was synthesized via microwave assisted combustion method using Alocasia odutra plant extract. • 71% mineralization of DCF was achieved within 50 min in the presence of sunlight. • SMF has more stability and low iron leaching capacity. • Efficiency of SMF were tested against different water matrices. • The carbonate ions and humic acid in water competes with the active radicals declined the catalytic activity of SMF. [ABSTRACT FROM AUTHOR]

In the current research work, a novel eco-friendly Fe 3 O 4 @SiO 2 nanocomposite immobilized with Pseudomonas fluorescens biomass in calcium alginate beads (MSAB) was used as biosorbent for the elimination of hazardous Rhodamine B dye from aqueous system. The FTIR, XRD and SEM results showed that the MSAB possessed excellent surface properties for the effective sequestration of Rhodamine B. The batch adsorption results concluded that the adsorption of Rhodamine B using MSAB is highly influenced by the parameters such as pH, adsorbent dosage, initial dye concentration and contact time. The equilibrium and kinetics data get best fitted in the Freundlich isotherm and Pseudo first order kinetics for the studied adsorption system. The Langmuir monolayer adsorption capacity was found to be 229.6 mg/g. The thermodynamic studies showed that the adsorption was spontaneous, feasible and exothermic in nature. The adsorption mechanisms are understood using the Intraparticle diffusion and Boyd model. Thus, this Magnetic silica alginate beads (MSAB) containing dead biomass of Pseudomonas fluorescens is considered to be an ideal biosorbent which can be used as an effective tool in treating the industrial dye wastewater treatment. Image 1 • Pseudomonas fluorescens was successfully incorporated in the magnetic silica. • MSAB biosorbent is eco-friendly in nature. • Adsorbent can be easily recovered using an external magnetic field. • The maximum monolayer adsorption capacity is found to be at 229 mg/g. • This adsorbent can reduce the secondary pollution. Main Finding: The effective separation of toxic dye from aqueous system was achieved using Magnetic Silica Nanocomposite Immobilized Pseudomonas fluorescens. [ABSTRACT FROM AUTHOR]

The utilization of fossil fuels causes adverse effects on the human and environment and the world is facing the depletion of these resources. The conventional technologies available for hydrogen production create greenhouse gases which cause a serious threat to the surroundings. Hence, there is a need to create a renewable and alternative technique for hydrogen production. The biological method acts as renewable technology to conventional technologies. For the present and future generations, the development of bioreactors may provide a sustainable route to meet cleaner hydrogen production. The conventional methods like reforming process, gasification process, thermochemical method, water electrolysis and photoelectrochemical method are not sustainable which emits toxic gases and requires a large amount of energy but in the application of bioreactors the cleaner fuel can be obtained and wastewater can be treated efficiently. The objectives of this review are to estimate the efficiency of reactors involving dark fermentation reactors (suspended and attached growth reactors), photobioreactors (tubular and flat plate reactors) and microbial electrolysis cell bioreactors along with their recent advancements in hydrogen production. This article also highlighted the comprehensive review about the substrate utilization, waste treatment, the principle of reactor process and recent process developments. Although several methods are available for hydrogen production, important and innovative discoveries and process configurations in pilot-scale are needed to estimate the potential of each bioreactor to provide sustainable and cleaner fuel production. Through this review, the present status of bioreactors in hydrogen production and their scale-up opportunities can be determined. • The recent advancements on the bioreactors for biohydrogen production has discussed. • Summarized the environmental conditions required for higher rate of hydrogen production. • Outlined the best reactor to bring the hydrogen production in industrial scale. • Explained the basis for managing the technical berries raised in hydrogen production. [ABSTRACT FROM AUTHOR]

The objective of the current study was focused on the potential adsorption capability of a biogenic hydroxyapatite/iron nanoparticles-based composite tailored for the elimination of toxic pollutant, Cd(II) ions. Morphological along with physicochemical properties of composites were analyzed by different techniques including Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDAX), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). It has been noticed an increase in cell parameters of prepared composites with an increase in the amount of nanoparticles. The best adsorbent was found to be the one with a 5% amount of nanoparticles (P 400 F e (5%)). The kinetics studies have shown that the pseudo-first-order-models were in good agreement for the removal of Cd(II) ions onto P 400 Fe(5%) at any concentration, suggesting a physisorption mechanism. Besides, isotherms analysis has consistently revealed Freundlich as the model better explained the isotherm data, with a maximum removal capacity of 392.3 mg g−1, higher compared to many adsorbents. Thermodynamically, the removal adsorption process of Cd(II) ions onto the composite favorable, exothermic, and spontaneous. The regeneration study has been also investigated with reusability used until four cycles. The overall results pointed out the suitability and efficiency of the prepared biogenic composite for the elimination of metal pollutants in wastewater. [Display omitted] • Biogenic composites were successfully prepared from slaughterhouses by-product and iron nanoparticles. • The maximum adsorption capacity of P 400 Fe(5%) was up to 392.3 mg g−1. • The isotherm and kinetic data best fits Freundlich and pseudo-first-order models. • The mechanism could be due to cationic exchange between Ca2+ and Cd2+. • The biogenic composite was effective for four consecutive regeneration cycles. [ABSTRACT FROM AUTHOR]