Synthesis of CoWO4/g-C3N4 Z-scheme heterojunction for the efficient photodegradation of diazinon with the addition of H2O2.

Pesticides are on the list of substances that are routinely monitored by agencies and organizations in various natural environments and habitats. Diazinon (DZN) is the active ingredient in more than 20 agricultural pesticides, it causes the most damage and has been prohibited in many countries around the world. The final product CoWO4/g-C3N4 Z-scheme heterojunction was successfully synthesized in this work, where CoWO4 nanoparticles were deposited on the surface of g-C3N4. CoWO4/g-C3N4 structure allowed for the efficient separation of photo-generated electron-hole pairs, with electrons at the CoWO4 CB migrating to the g-C3N4 VB and preserving the electrons at the g-C3N4 CB and holes in the CoWO4 VB. The photodegradation efficiency of DZN using CoWO4/g-C3N4 Z-scheme heterojunction was investigated, as compared with its precursors, such as CoWO4, and g-C3N4. CoWO4/g-C3N4 Z-scheme heterojunction demonstrated the highest degradation capacity for DZN removal. Based on the results, the photocatalysis of the CoWO4/g-C3N4 Z-scheme heterojunction can be recycled for the effective removal of DZN by simple washing after three runs, proving the heterojunction's stability and suggesting CoWO4 as a promising material for the removal of DZN from contaminated water sources.

Synthesis of Iron Oxide Nanoparticle Functionalized Activated Carbon and Its Applications in Arsenic Adsorption.

This work reveals the As(V) adsorption behaviors onto iron oxide (Fe3O4) nanoparticles modified activated carbon (AC), originally developed from biochar (BC), as a green adsorbent denoted by FAC. Since FAC has abundant surface functional groups and a desired porous structure that is favorable for the removal of As(V) in contaminated water, FAC has greatly enhanced the As(V) adsorption capacity of the original BC. Various methods were employed to characterize the FAC characteristics and adsorption mechanism, including pHpzc determination, BET specific surface area, elemental analysis (EA), and scanning electron microscopy (SEM). Results show that the AC surface was successfully modified by iron oxide nanoparticles, enhancing the porosity and specific surface area of original adsorbent. Batch adsorption tests indicated a well-fitted Langmuir model and pseudo-second-order model for As(V) adsorption. Additionally, the highest adsorption capacity (Q max = 32.57 mg/g) by FAC was higher than previously reported literature reviews. Until now, no article was conducted to research the effect of carbon surface chemistry and texture on As removal from waters. It is required to obtain a rational view of optimal conditions to remove As from contaminated water.

Removal of Heavy Metal Ion Using Polymer-Functionalized Activated Carbon: Aspects of Environmental Economic and Chemistry Education.

Numerous countries have shown signs of environmental pollution to prioritize economic growth and benefits, leading to seriously contaminated waters. This work indicated the method to synthesize a green material, which could remove contaminants to protect the natural environment. The porosity and functionality effects of amine-functionalized activated carbon (AFAC) enhanced the removal of toxic heavy metals (THMs) in aqueous solution. The raw activated carbon (RAC) was thermally modified with ultrahigh pure nitrogen (UHPN) at 500°C and 1000°C and then amine-functionalized with coupling agent of aminopropyltriethoxysilane (APS). They were denoted as AFAC-5 and AFAC-10, respectively. The data showed an enhanced metal adsorption capacity of the AFACs, because the modification produced more desired porosity and increased amine functional groups. AFAC-10, modified at a higher temperature, showed much higher THM adsorption capacity than AFAC-5, modified at a lower temperature, and RAC. The adsorption capacity decreased in the following order: Ni > Cd > Zn, which was in good agreement with the increasing electronegativity and ionic potential and the decreasing atomic radius. The maximum THM adsorption capacity of AFAC-10 for Ni, Cd, and Zn was 242.5, 226.9, and 204.3 mg/g, respectively.

Ternary cross-coupled nanohybrid for high-efficiency 1H-benzo[d]imidazole chemisorption.

1H-Benzo[d]imidazole (BMA) has been considered as an emerging pharmaceutical organic contaminant, leading to the increasing BMA detection in wastewaters and need to be removed from ecosystem. This study investigated a highly synergistic BMA chemisorption using a novel ternary cross-coupled nanohybrid [γ-APTES]-Fe3O4@PAN@rGO. Magnetic nanoparticles (Fe3O4) were in situ core-shell co-precipitated with polyacrylonitrile polymer (PAN). Then, the prepared Fe3O4@PAN was decorated on hexagonal arrays of reduced graphene oxide (rGO) inside the framework of γ-aminopropyltriethoxysilane ([γ-APTES]). The final nanohybrid [γ-APTES]-Fe3O4@PAN@rGO produced adjacent inter-fringe distances of 0.2-0.4 nm corresponded well to (111), (220), and (311) parallel sub-lattices with two oblique intersections at 90° right angle and 60° triangle. The BMA adsorption was favorable in neutral pH 7, aroused temperature (50 °C), and controlled by endothermic process. The identified maximum adsorption capacity of 221.73 mg g-1 was 30% higher than the reported adsorbents. The adsorption mechanisms include ion exchange, hydrogen bond, dipole-dipole force, π-conjugation, electrostatic, and hydrophobic interaction. Graphical abstract The synthetic route of novel nanohybrid [γ-APTES]-Fe3O4@PAN@rGO was investigated. After BMA adsorption, the adsorbent surface was entirely changed, thus an efficiently facile magnetic separation within 8s. [γ-APTES]-Fe3O4@PAN@rGO formed different oblique intersections of 60° and 90° sub-lattices.

Methanol-dispersed of ternary Fe3O4@γ-APS/graphene oxide-based nanohybrid for novel removal of benzotriazole from aqueous solution.

A novel nanohybrid: Fe3O4 coated with γ-APS polymer deposited on graphene oxide (F@γ-A/G), to remove an emergent heterocyclic contaminant benzotriazole (BTA) from solution. F@γ-A/G was synthesized in methanol-dispersion via aminosilanization under ultra-sonication. We newly found that F@γ-A/G crystallite lattice has a 2D triangular-network intersection with angle of 60° in three types of d311, d220 and d111 planes with different interplanar spacings. Textural characteristics did not affect BTA adsorption, which was desired at high temperature (40 °C), neutral solution (pH = 6) and controlled by endothermic process. Considering the maximum BTA adsorption capacity of 312.5 mg/g, which was much higher than previously reported adsorbents, the plausible mechanism was attributed to hydrophobic, electrostatic and π-π interaction. Effects of pH and temperature are significant on BTA adsorption to F@γ-A/G. Methanol was the best solvent for multiple cycle regeneration with only 2% loss of BTA removal efficiency even after five cycles of F@γ-A/G.