Selective Adsorption Behavior and Mechanism for Cd(II) in Aqueous Solution with a Recoverable Magnetie-Surface Ion-Imprinted Polymer.

A novel recoverable magnetic Cd(II) ion-imprinted polymer was synthesized on the surface of silica-coated Fe3O4 particles via the surface imprinting technique and chemical grafting method. The resulting polymer was used as a highly efficient adsorbent for the removal of Cd(II) ions from aqueous solutions. The adsorption experiments revealed that Fe3O4@SiO2@IIP had a maximum adsorption capacity of up to 29.82 mg·g-1 for Cd(II) at an optimal pH of 6, with the adsorption equilibrium achieved within 20 min. The adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm adsorption model. Thermodynamic studies showed that the adsorption of Cd(II) on the imprinted polymer was spontaneous and entropy-increasing. Furthermore, the Fe3O4@SiO2@IIP could rapidly achieve solid-liquid separation in the presence of an external magnetic field. More importantly, despite the poor affinity of the functional groups constructed on the polymer surface for Cd(II), we improved the specific selectivity of the imprinted adsorbent for Cd(II) through surface imprinting technology. The selective adsorption mechanism was verified by XPS and DFT theoretical calculations.

Two 6/10-connected Cu12S6 cluster-based organic frameworks: crystal structure and proton conduction.

Nowadays, although the exploration of proton conductive materials has ranged from traditional sulfonated polymers to novel crystalline solid materials such as MOFs, COFs, and HOFs, research on crystalline cluster-based organic framework materials is very limited. Here, a pair of homologues Cu(i)-based organic framework containing a Cu12S6 cluster, [Cu12(MES)6(H2O)3]n (1) and {[Cu12(MPS)6(H2O)4]·6H2O}n (2) (H2MES = 2-mercaptoethanesulfonate acid and H2MPS = 2-mercaptoethanesulfonate acid), were hydrothermally synthesized under the same conditions and fully investigated for their proton conduction. Their structures were characterized by means of single-crystal X-ray diffraction, elemental analysis, thermogravimetric analyses, and PXRD measurements. The two MOFs show significant structural differences in the topological fashions. MOF 1 has a three-dimensional network and can be simplified into two topology types: a 10-connected gpu structure with a Schläfli symbol (312·426·57) and a 3,12-connected new topology with a point symbol {3·42}2{310·418·519·614·74·9}. MOF 2 also has a three-dimensional framework and topology as a 6-connected pcu primitive cubic network with a Schläfli symbol {412·63}. The two MOFs show different proton conduction parameters, but both indicate temperature-dependent proton conductive features. Intriguingly, the two MOFs exhibit high water stability and their proton conductivities are 3.63 × 10-5 and 2.75 × 10-5 S cm-1 under 333 K and 98% RH, respectively. The suggested mechanism for the synthesis for 1 and 2, and their proton conductivity performance comparison has been discussed in detail. In addition, Hirshfeld surface and fingerprint analysis on the two MOFs were computed to compare contacts between the molecules, which is essential for analyzing the relationships between their hydrogen bonds and proton conductivity properties.

Accelerated phosphorus recovery from aqueous solution onto decorated sewage sludge carbon.

In search of efficient phosphorus resource recovery and pollution remediation should be highly concerned due to the view of phosphorus nonrenewable and eutrophication. This work presented a new insight into conversion of sewage sludge into favorable carbonaceous adsorbent for accelerated removing and recovering phosphorus from aqueous solution, what addressed the issues of phosphorus recovery and pollution remediation as well as sludge disposal. Ca and water hyacinth were evolved to decorate sludge derived carbon. Effect of mass ratio of sludge, water hyacinth and calcium carbonate on the morphologies and adsorption kinetics was investigated. The adsorbents (SW-Ca-112) resulted from sludge in the presence of water hyacinth and CaCO3 in a mass ratio of 1:1:2 had the highest adsorption capacity of 49.50 mg/g P and adsorption rate. Decoration of Ca favored adsorption ability and the presence of water hyacinth accelerated the adsorption rate due to the enhanced porosity. Formation of acicular Ca5(PO4)3OH nanoparticles contributed to the favorable adsorption process. Thus, the contribution of decorated Ca and water hyacinth to the adsorption ability and rate to phosphorus was understand, providing important information on resource utilization of sewage sludge as efficient adsorbent for immobilizing phosphorus from aqueous solution.