Amino‐Functionalized Multilayer Core–Shell Mesoporous Organosilica Nanospheres for Cr(VI) Removal

Abstract

Developing low-cost and highly efficient adsorbents for the removal of toxic heavy metal ions has been the subject of intensive research with the increasingly stringent water pollution control standards. In this paper, three types of amino-functionalized multi-layer core-shell mesoporous organosilica nanospheres (MCMONs) have been synthesized using an indirect co-condensation method for Cr(VI) removal applications. Results show that amino groups have been successfully immobilized on the nanospheres and these amino-functionalized MCMONs exhibit unique organic-inorganic multi-layer core-shell structures . When used as adsorbent for Cr(VI) removal, our N-(3-trimethoxysilylpropyl)diethylenetriamine functionalized MCMONs exhibits an maximum adsorption capacity of 279.92 mg/g at initial Cr(VI) concentration of 150 mg/L. This is about 20% greater than the highest Cr(VI) adsorption capacity previously reported for other core-shell silica-based adsorbents, demonstrating the great potential of our MCMONs in Cr(VI) removal applications.

MCM-41-based composite with enhanced stability for Cr(VI) removal from aqueous media

“…Parida et al reported a higher q max without Cr (VI) reduction using an MCM-41-based sorbent modified with TiO 2 , this was related with the zero point charge of the sorbent surface at the selected pH value of 5.5 [49]. In the cases were Cr(VI) reduction was detected the behavior is not linear and a broad q max values are reported [14,50,51]. For example it was determined that the silica particle size has an important effect on the sorbent performance; as the sorbent particle size decreases the efficiency in chromium removal increases.…”

“…For example, Bao and coworkers synthesized porous NH 2 -MCM-41 nanoparticles with uniform hydrophilic and adsorptive surface which shows good adsorption capacity for Cr (VI) reaching equilibrium around 5 min [13]. Lai et al synthesized three types of amino-functionalized mesoporous nanospheres using an indirect co-condensation method and applied this nanocomposites for Cr(VI) removal at experiments conducted under room temperature using Cr-contained solution (100 mL, 20 mg LÀ 1) under pH 3, finding a maximum adsorption capacity of 279.92 mg g À 1 for the N-(3-trimethoxysilylpropyl)diethylenetriamine functionalized composite [14].…”

Aqueous-Phase Nanomolar Detection of Dichromate by a Recyclable Cd(II) Metal–Organic Framework

“…On the basis of the above considerations, herein, a conjugated aromatic linker, namely quinoline-2,6-dicarboxylic acid (H 2 QDA) (Figure S1 in the Supporting Information), has been chosen with the d 10 Cd(II) ion to construct a unique three-dimensional Cd(II)-MOF (1). The as-synthesized compound 1 with the formula {[Cd(QDA)]•DMF•0.5H 2 O} n was prepared by a employing solvothermal method.…”

“…The sensitive and selective detection of toxic anions such as SeO 3 2– , AsO 4 3– , and Cr 2 O 7 2– in the environment is currently of utmost importance. Among these toxic anions, Cr 2 O 7 2– is widely used in the field of glass manufacturing, agriculture, the production of stainless steel, the manufactuting of chromite, oxidative dyeing, wood preservation, paint manufacturing, etc. , The excessive use of Cr 2 O 7 2– by industry can cause severe environmental pollution. Toxic Cr 2 O 7 2– is a strong oxidizing agent, which can be accumulated in living organisms.…”

Cationic Metal–Organic Framework-Based Mixed-Matrix Membranes for Fast Sensing and Removal of Cr2O72− Within Water

“…Heavy metal pollution has become a severe environment threat around the world. Hexavalent chromium ions, especially Cr 2 O 7 2− , has been widely employed in various industrial applications, such as metallurgy, pigment production, leather tanning, electroplating, and other relevant fields ( Desai et al, 2016 ; Lai et al, 2018 ; Li et al, 2018 ). According to the U.S.…”