Phenolic compounds are priority pollutants with high toxicity even at low concentrations. In this review, the efficiency of both conventional and advanced treatment methods is discussed. The applicability of these treatments with phenol and some common derivatives is compared. Conventional treatments such as distillation, absorption, extraction, chemical oxidation, and electrochemical oxidation show high efficiencies with various phenolic compounds, while advanced treatments such as Fenton processes, ozonation, wet air oxidation, and photochemical treatment use less chemicals compared to the conventional ones but have high energy costs. Compared to physico-chemical treatment, biological treatment is environmentally friendly and energy saving, but it cannot treat high concentration pollutants. Enzymatic treatment has proven to be the best way to treat various phenolic compounds under mild conditions with different enzymes such as peroxidases, laccases, and tyrosinases. This review covers papers from 2013 through January 2016.

/pdf/a-short-review-of-techniques-for-phenol-removal-from-2iihuqdwlr.pdf

A Short Review of Techniques for Phenol Removal from Wastewater

Selective oxidation has an important role in environmental and green chemistry (e.g., oxidative desulfurization of fuels and oxidative removal of mercury) as well as chemicals and intermediates chemistry to obtain high-value-added special products (e.g., organic sulfoxides and sulfones, aldehydes, ketones, carboxylic acids, epoxides, esters, and lactones). Due to their unique physical properties such as the nonvolatility, thermal stability, nonexplosion, high polarity, and temperature-dependent miscibility with water, ionic liquids (ILs) have attracted considerable attention as reaction solvents and media for selective oxidations and are considered as green alternatives to volatile organic solvents. Moreover, for easy separation and recyclable utilization, IL catalysts have attracted unprecedented attention as “biphasic catalyst” or “immobilized catalyst” by immobilizing metal- or nonmetal-containing ILs onto mineral or polymer supports to combine the unique properties of ILs (chemical and thermal stabili...

Ionic Liquids in Selective Oxidation: Catalysts and Solvents

Chromium reaches the soil environment through waste disposal emanating from a number of industrial activities, including coal-fired power production, electroplating, leather tanning, timber treatment, pulp production, and mineral ore and petroleum refining. Of the heavy metals, chromium (Cr) is a major pollutant, poses a great threat to flora and fauna and persists for long time. The most abundant species of Cr—Cr(III) and Cr(VI)—have very different properties. The toxicity, mobility, and bioavailability of Cr mainly depend on its speciation. In the natural environment, Cr(III) is most immobile, less soluble and stable, whereas Cr(VI) is highly mobile, soluble and bioavailable. Redox reactions play an important role in the interconversion of Cr(VI) and Cr(III). As our awareness of the rising toxicity of Cr increases, it is necessary to develop new and advanced strategies to mitigate this toxicity in the environment. Several physicochemical methods have been developed but these techniques are expensive and are not readily applicable to large contaminated zones. This chapter provides an overview of the concepts of Cr biogeochemistry, bioavailability and integrated risk management. The physicochemical factors, speciation and toxicity have been discussed with special emphasis on the remediation methods due to the complex reactions associated with Cr toxicity mitigation. Furthermore, this study identified systematically the future needs for understanding Cr biogeochemistry and low-cost remediation methods.

Chromium contamination and its risk management in complex environmental settings

Molecular imprinting-based solid-phase extraction (MI-SPE) has been in the spotlight to improve the recognition selectivity and detection sensitivity. MI-SPE provides a powerful tool for chemo/bioanalysis in complex matrices and meanwhile, benefits from distinguished advantages such as easy operation, high throughput, low cost, high selectivity and durability. This review proposed the recent advances in molecular imprinting concerning novel preparation strategies of molecularly imprinted polymers (MIPs) and typical applications of MI-SPE. Preparation strategies are highlighted by dividing into ten sections mainly including dummy imprinting, multi-template imprinting, surface imprinting, water-compatible imprinting, restricted access material combining imprinting etc.; each section provides the descriptions about what restrictions led to the emergence of any strategy, strengths/weaknesses of every strategy and universal applications of upgraded MIPs in various SPE modes prior to chromatographic analysis. The potential of MIPs for implementation in routine laboratory activities and scale-up is expected, and finally remaining challenges and future perspectives are proposed.

Strategies of molecular imprinting-based solid-phase extraction prior to chromatographic analysis

Recent advances in carbon nanomaterial-based adsorbents for water purification

Degradation of organic pollutants in near-neutral pH solution by Fe-C micro-electrolysis system

Preparation and adsorption characteristics of an ion-imprinted polymer for fast removal of Ni(II) ions from aqueous solution

To achieve a fast adsorption rate and a high adsorption capacity in the selective adsorption of Cr(VI) from wastewater, a novel Cr(VI) ion imprinted polymer (Cr(VI)-IIP) was synthesized by bulk polymerization with ethylene glycol dimethacrylate as a crosslinking agent, azodiisobutyronitrile as an initiator, and acetone as a solvent Eight functional monomers, including acidic, basic and neutral agents, were investigated in the synthesis of Cr(VI)-IIPs The Cr(VI)-IIP prepared with 4-vinyl pyridine (4-VP) as a functional monomer provided the highest adsorption capacity, which was characterized by Fourier infrared spectroscopy, zeta potential, Brunauer, Emmett and Teller and scanning electron microscopy The influences of functional monomer amount, crosslinking agent, initiator, solvent, pH in aqueous solution, initial Cr(VI) concentration, and so on, on adsorption performance were studied The adsorption process of Cr(VI)-IIP followed a pseudo-second-order kinetic model and Langmuir adsorption isotherm model The electrostatic interactions between Cr(VI) anion and the protonated N atoms of the functional pyridine groups on prepared IIPs could enhance the adsorption capacity and adsorption rate Under the optimal operating conditions, the maximum adsorption capacity of Cr(VI)-IIP prepared with 4-VP was up to 33873 mg g−1, and the adsorption equilibrium was reached within 3 min The Cr(VI)-IIPs also showed good selectivity, reusability and stability The selectivity coefficient was up to 18905 and 9656 for Cr(VI)/Cu(II) and Cr(VI)/Cr(III), respectively

Preparation and adsorption characteristics of an imprinted polymer for selective removal of Cr(VI) ions from aqueous solutions

A fluoride-free ionic liquid 1-butyl-3-methylimidazolium phosphotungstate ([Bmim]3PW12O40) was synthesized and first used as co-extraction reagent for recovery of lithium ions from salt lake brine ...

Recovery of Lithium Ions from Salt Lake Brine with a High Magnesium/Lithium Ratio Using Heteropolyacid Ionic Liquid

A novel Cr(VI) ion imprinted polymer (IIP) was proposed for fast removal of Cr(VI) from aqueous solution. 4-Vinylpyridine and N,N-diethylaminoethyl methacrylate were used as functional monomers, and ethylene glycol dimethacrylate and 2,2-azoisobisbutyronitrile were used as cross-linker and initiator in the presence of a binary porogenic solvent. The prepared Cr(VI)-IIPs were characterized by the Fourier transform infrared spectroscopy and scanning electron microscopy. The effects of pH, initial concentration of Cr(VI) in aqueous solution, temperature, and operating time on adsorption were investigated. At the low pH range of 1.5–2.5, the adsorption capacities were high. The influence of temperature was slight. The adsorption equilibrium time was within 3 min. The adsorption process followed the pseudo-second-order equation and the Langmuir isotherm model. The maximum adsorption capacity was up to 286.56 mg/g, and the selectivity factors of Cr(VI)/Cu(II), Cr(VI)/Cd(II), and Cr(VI)/Cr(III) were up to 135.78...

Zhongqi Ren

Papers

Degradation of organic pollutants in near-neutral pH solution by Fe-C micro-electrolysis system

Preparation and adsorption characteristics of an ion-imprinted polymer for fast removal of Ni(II) ions from aqueous solution

Preparation and adsorption characteristics of an imprinted polymer for selective removal of Cr(VI) ions from aqueous solutions

Recovery of Lithium Ions from Salt Lake Brine with a High Magnesium/Lithium Ratio Using Heteropolyacid Ionic Liquid

Fast Removal of Cr(VI) from Aqueous Solution Using Cr(VI)-Imprinted Polymer Particles