We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

Mn3O4-Graphene Hybrid as a High Capacity Anode Material for Lithium Ion Batteries

A critical review on textile wastewater treatments: Possible approaches.

Highly efficient removal of metal ion pollutants, such as toxic and nuclear waste-related metal ions, remains a serious task from the biological and environmental standpoint because of their harmful effects on human health and the environment. Recently, highly porous metal–organic frameworks (MOFs), with excellent chemical stability and abundant functional groups, have represented a new addition to the area of capturing various types of hazardous metal ion pollutants. This review focuses on recent progress in reported MOFs and MOF-based composites as superior adsorbents for the efficient removal of toxic and nuclear waste-related metal ions. Aspects related to the interaction mechanisms between metal ions and MOF-based materials are systematically summarized, including macroscopic batch experiments, microscopic spectroscopy analysis, and theoretical calculations. The adsorption properties of various MOF-based materials are assessed and compared with those of other widely used adsorbents. Finally, we propose our personal insights into future research opportunities and challenges in the hope of stimulating more researchers to engage in this new field of MOF-based materials for environmental pollution management.

Metal–organic framework-based materials: superior adsorbents for the capture of toxic and radioactive metal ions

The use of zero-valent iron for groundwater remediation and wastewater treatment: a review.

Traditional physicochemical and biological techniques, as well as advanced oxidation processes (AOPs), are often inadequate, ineffective, or expensive for industrial water reclamation. Within this context, the electrochemical technologies have found a niche where they can become dominant in the near future, especially for the abatement of biorefractory substances. In this critical review, some of the most promising electrochemical tools for the treatment of wastewater contaminated by organic pollutants are discussed in detail with the following goals: (1) to present the fundamental aspects of the selected processes; (2) to discuss the effect of both the main operating parameters and the reactor design on their performance; (3) to critically evaluate their advantages and disadvantages; and (4) to forecast the prospect of their utilization on an applicable scale by identifying the key points to be further investigated. The review is focused on the direct electrochemical oxidation, the indirect electrochemical oxidation mediated by electrogenerated active chlorine, and the coupling between anodic and cathodic processes. The last part of the review is devoted to the critical assessment of the reactors that can be used to put these technologies into practice.

Single and Coupled Electrochemical Processes and Reactors for the Abatement of Organic Water Pollutants: A Critical Review.

Comparative decolorization of dyes in textile wastewater using biological and chemical treatment

Magnetic biochar is increasingly known as a multi-functional material and the appropriate synthesis method further increase its efficient applications. In this study, the effects of synthesis methods on the fabrication of Kans grass straw/biochar (KGS/KGB) with Fe3+/Fe2+ by chemical co-precipitation and subsequently pyrolyzing at 500 °C for 2 and 4 h were studied in details, and compared their As(III, V) adsorption potentials under different operating conditions. Magnetic biochars (MKGB3 and MKGB4) prepared from KGS revealed of superior Fe3O4 loading, higher As(III, V) adsorption efficiency and saturation magnetization (45.7 Am2 kg−1) than that of KGB (MKGB1 and MKGB2). Moreover, Thermogravimetric analysis (TGA) demonstrated three stages of decomposition and the MKGB3 and MKGB4 generated higher residual mass (>60%) at stage 3 (1000 °C) due to greater Fe3O4 composite in biochar matrix and turned to be thermally more stable. As(III) and As(V) adsorption equilibrium data well fitted in Langmuir model and followed the order: MKGB4 > MKGB3 > MKGB2 > MKGB1. The maximum As(III) and As(V) adsorption capacities were about 2.0 mg g−1 and 3.1 mg g−1, respectively. The data best fitted in pseudo-second-order (R2 > 0.99) rather than pseudo-first-order kinetics model indicating of more complex mechanism. The adsorption of As(III) and As(V) was found to decrease with increasing in ionic strength of competing ions and PO43− was found to strongly inhibit arsenic adsorption. Highest desorption was achieved at pH 13.5 using NaOH. This study suggests that selective adsorbent synthesis method could be useful to prepare effective adsorbent for toxic metals immobilization.

Effect of synthesis methods on magnetic Kans grass biochar for enhanced As(III, V) adsorption from aqueous solutions

Multifunctional nanocomposites Fe3O4@SiO2-EDTA for Pb(II) and Cu(II) removal from aqueous solutions

Fe3O4 and MnO2 assembled on honeycomb briquette cinders (HBC) for arsenic removal from aqueous solutions.

Elevated arsenic concentrations have been detected in drinking water sources worldwide and it threatens to over 200 million people in both developing and developed countries. Adsorption is a conventional process for arsenic removal from contaminated water. Several classes of adsorbing materials have been tested so far. However, far less attention was paid towards granular-based adsorption and granulation processes. The present work is the first attempt to consider both the granular adsorbent and the granulation process. A particular emphasis was given to cost-efficient adsorbent for small scale arsenic removal. Some of the features of granular adsorbents are summarized in tables and graphs; address necessary outlines for readers to easily overview the adsorbents' characteristics and design sustainable adsorption system. Earlier, cost of arsenic removals from granular adsorbents were not widely affirmed, but in this review few of them are incorporated for comparisons in future studies. Thus, one gram of arsenic removal from water using novel and iron oxide-coated sand adsorbents is approximately ranged US$2.3–5.1 and US$3.3–4.2, respectively. Moreover, methods employed for regeneration of exhausted granular adsorbents are discussed. Field scale arsenic remediation measures and the performance evaluations are additionally reported to identify the feasibility of these approaches for scaling up, awareness raising and promotion.

Shams Ali Baig

Papers

Comparative decolorization of dyes in textile wastewater using biological and chemical treatment

Effect of synthesis methods on magnetic Kans grass biochar for enhanced As(III, V) adsorption from aqueous solutions

Multifunctional nanocomposites Fe3O4@SiO2-EDTA for Pb(II) and Cu(II) removal from aqueous solutions

Fe3O4 and MnO2 assembled on honeycomb briquette cinders (HBC) for arsenic removal from aqueous solutions.

Arsenic removal from natural water using low cost granulated adsorbents: a review.