Inclusion of bimetallic Fe0.75Cu0.25-BDC MOFs into Alginate-MoO3/GO as a novel nanohybrid for adsorptive removal of hexavalent chromium from water.

Metal-organic frameworks (MOFs) as porous materials have recently attracted research works in removal of toxic pollutants from water. Cr(VI) is well-known as one of the most toxic forms of chromium and the selection of efficient and effective Cr(VI)-remediation technology must be focused on a number of important parameters. Therefore, the objective of this work is to fabricate a novel nanohybrid adsorbent for removal of Cr(VI) by using assembled bimetallic MOFs (Fe0.75Cu0.25-BDC)-bound- Alginate-MoO3/Graphene oxide (Alg-MoO3/GO) via simple solvothermal process. The aimed Fe0.75Cu0.25-BDC@Alg-MoO3/GO nanohybrid was confirmed by FTIR, SEM, TEM, XRD and TGA. Adsorptive extraction of Cr(VI) from aqueous solution was aimed by various optimized experimental parameters providing optimum pH = 3, dosage = 5-10 mg, starting concentration of Cr(VI) = 5-15 mg L-1, shaking time = 5-10 min. The point of zero charge (pHPzc) was 3.8. For Cr(VI) removal by Fe0.75Cu0.25-BDC@Alg-MoO3/GO, four isotherm models were estimated: Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) with calculated correlation coefficient (R2 = 0.9934) for Langmuir model which was higher than others. The collected results from the kinetic study clarified that pseudo-second order model is the most convenient one for describing the adsorption behavior of Cr(VI) and therefore, the adsorption process was suggested to rely on a chemisorption mechanism. Thermodynamic parameters referred that the adsorption mechanism is based on a spontaneous and exothermic process. Finally, the emerged Fe0.75Cu0.25-BDC@Alg-MoO3/GO nanohybrid was confirmed as an effective adsorbent for extraction of hexavalent chromium from real water specimens (tap, sea water and wastewater) with percentage recovery values > 98%.

Effective removal of levofloxacin drug and Cr(VI) from water by a composed nanobiosorbent of vanadium pentoxide@chitosan@MOFs.

Wastewaters is generally polluted with various inorganic and organic contaminants which require effective multipurpose purification technology. In this respect, a novel V2O5@Ch/Cu-TMA nanobiosorbent was constructed via encapsulation of nanoscale metal organic frameworks (Cu-TMA) into vanadium pentoxide-imbedded-chitosan matrix to comprehensively investigate its efficiency in removal of levofloxacin drug (LEVO) (e.g., organic pollutant) and chromium (VI) (e.g., inorganic pollutant) from water. Both LEVO drug and Cr(VI) adsorptions were correlated to pseudo-second order (R2 = 1) and Langmuir isotherm (R2 = 0.9924 for LEVO and R2 = 0.9815 for Cr(VI)). Adsorption of Cr(VI) was confirmed to be spontaneous and endothermic reactions, while LEVO was found to proceed via spontaneous and exothermic reactions based on the thermodynamic parameters. The emerged V2O5@Ch/Cu-TMA is regarded as an excellent nanobiosorbent for removal of inorganic contaminant as Cr(VI) from all natural water samples (tap, sea and wastewater) with percentages range 92.43%-96.95% and organic contaminant as LEVO drug from tap and wastewater (91.99%-97.20%).

Removal of uranium (VI) from water by the action of microwave-rapid green synthesized carbon quantum dots from starch-water system and supported onto polymeric matrix.

Carbon quantum dots (CQDs) are a new class of carbon nanoparticles with superior advantages as small particle size, excellent biocompatibility and low toxicity which advance their recent applications in biotechnology, bioimaging and biosensing. The use of free CQDs in water treatment is greatly rendered by their high solubility in water. Therefore, this work is aimed to rapidly synthesize CQDs in only 10 min via microwave irradiation pyrolysis of starch-water system. The maximum fluorescence emission of CQDs was detected at 526 nm throughout the excitation wavelength (390 nm). The CQDs have been targeted to occupy the surface and pores of a polymeric material based on poly(anthranilic acid-formaldehyde-phthalic acid) (PAFP) to produce a novel CQDs@PAFP nanobiosorbent. The surface area of CQDs@PAFP was detected (28.79 m2 g-1 BET) and the nanoparticle size was confirmed (TEM). The highest removals of U(VI) by CQDs@PAFP nanobiosorbent were 95.5-98.0 % for 30-90 mg L-1. The sorption mechanism was designated to the pseudo-second-order model and closely tailored with Freundlich model. CQDs@PAFP was emerged as an excellent nanobiosorbent for U(VI) removal from wastewater (97.3 %) and sea water (96.0 %). CQDs@PAFP confirmed its excellent reusablity for efficient multi- recovery of U(VI) from different water samples.

A novel nanobiosorbent of functionalized graphene quantum dots from rice husk with barium hydroxide for microwave enhanced removal of lead (II) and lanthanum (III).

In this study, rice husk was used as a sustainable source to synthesize graphene quantum dots (GQDOs) with 2D morphology. Chemical modification of GQDOs with Ba(OH)2 was followed to form a novel GQDOs-Ba nanobiosorbent with an increased number of surface hydroxyl groups. The physicochemical properties of GQDOs and GQDOs-Ba were investigated by FT-IR, SEM, TEM, TGA, and XRD. The adsorption parameters of Pb(II) and La(III) onto GQDOs-Ba were optimized using microwave sorption approach. The maximum capacity reached 3400 µmol g-1 (pH 7), and 1500 µmol g-1 (pH 5) at 15 s for Pb(II) and La(III), respectively. The adsorption isotherm models by GQDOs-Ba fitted well with Langmuir. The pseudo-second order was agreed by Pb(II) and La(III) ions. The thermodynamic studies elucidated that Pb(II) and La(III) adsorption onto GQDOs-Ba followed a spontaneous model. The GQDOs-Ba nanobiosorbent accomplished excellent removal percentages from different water samples containing lead (98.5%-99.8%) and lanthanum (94.6%-96.2%).