Hydrothermal Fabrication of Fe3O4@Carbonaceous Microspheres for Efficient Removal of Oil and Metal Ions from the Aqueous Phase

Nanotechnology- A ray of hope for heavy metals removal

Environmental effects of heavy metal pollution are considered as a widespread problem throughout the world, as it jeopardizes human health and also reduces the sustainability of a cleaner environment. Removal of such noxious pollutants from wastewater is pivotal because it provides a propitious solution for a cleaner environment and water scarcity. Adsorption treatment plays a significant role in water remediation due to its potent treatment and low cost of adsorbents. In the last two decades, researchers have been highly focused on the modification of adsorption treatment by functionalized and surface-modified nanomaterials which has spurred intense research. The characteristics of nano adsorbents attract global scientists as it is also economically viable. This review shines its light on the functionalized nanomaterials application for heavy metals removal from wastewater and also highlights the importance of regeneration of nanomaterials in the view of visualizing the economic aspects along with a cleaner environment. The review also focused on the proper disposal of nanomaterials with crucial issues that persist in the adsorption process and also emphasize future research modification at a large-scale application in industries.

Efficient photocatalytic removal of phthalates easily implemented over a bi-functional {001}TiO2 surface

It is stubborn to remove the lowly concentrated phthalic acid esters (PAEs) that usually coexist with other highly concentrated but low-toxic pollutants in municipal sewage. Herein, we report a novel strategy for completely removing the PAEs over a bi-functional {001}TiO₂ surface (with highly exposed {001} facet), which not only serve as functional sites to specifically adsorb the target PAEs pollutants, but also contribute to an enhanced oxidation ability. The adsorption behavior of PAEs on {001}TiO₂ is analyzed deeply through kinetic experiments combining with in situ ATR-FTIR spectroscopy and theoretical calculations. The results reveal that the adsorption capacities of PAEs on {001}TiO₂ are about 4-5 times higher than that on TiO₂, both of which follow the pseudo-second-order and Langmuir model. This is mainly attributed to the interfacial Lewis Acid-Base Pair between {001} facet Ti_5c sites and CO of PAEs. Benefitting from the specific adsorption capability toward target pollutant and enhanced oxidation ability of {001} facets, nearly 100% of DMP or DEP in simulated wastewater can be eliminated by {001}TiO₂ within 2 h illumination, and the relevant degradation rate constants (k) (3.67 h^-1 for DMP and 2.19 h^-1 for DEP) are 5.73 and 3.08 folds higher than that of pure TiO₂, respectively. In the application of municipal wastewater, nearly 76% of DMP and 85% DEP can be eliminated by {001}TiO₂ within 2 h illumination, which are nearly 3-6 fold higher than that of pure TiO₂.

Recyclable polyether–polyquaternium grafted SiO2 microsphere for efficient treatment of ASP flooding-produced water: oil adsorption characteristics and mechanism

In this work, an interfacially active PPA@SiO₂ microsphere for ASP flooding-produced water treatment was synthesized by grafting polyether–polyquaternium (PPA) copolymer onto mesoporous hydrated silica (SiO₂). This PPA@SiO₂ microsphere integrates both demulsification and adsorption functionalities. The physicochemical properties of the SiO₂ variants were monitored via SEM, BET, XPS, contact angle and zeta potential tests. When disposing of a simulated alkali–surfactant–polymer flooding produced water that contained 500 mg L⁻¹ oil, this functional PPA@SiO₂ microsphere exhibited an oil removal efficiency of 78.0% at 1.0 g L⁻¹ dosage, which is higher than that of pristine SiO₂ (39.1%) and hydrophobic modified SiO₂ (54.2%). This remarkable oil removal efficiency was attributed to its abilities to destabilize and aggregate the emulsified oil droplets. Oil micromorphology test results indicated that PPA@SiO₂ could aggregate the fine oil droplets into oil clusters, which significantly favors the oil–water separation efficiency. An adsorption kinetics and thermodynamics study manifested that oil adsorption onto PPA@SiO₂ was an exothermic process, mainly dominated by external surface adsorption, which agreed with the BET and micromorphology study. Furthermore, the oil adsorption mechanism has been explored and confirmed according to all the experimental results. This modification protocol significantly reduced the PPA consumption and it was also found that the loaded oil onto PPA@SiO₂ could be effectively separated through a petroleum ether extraction process, so as to recycle the carrier particles. This novel PPA@SiO₂ microsphere with its high oil removal efficiency offers technical promise and huge potential for oily wastewater treatment.

A recyclable functional microsphere was developed which significantly enhances oil–water separation and decreases chemical demulsifier consumption.