Method for preparing amorphous molybdenum oxide adsorption material and application thereof

Abstract

The invention relates to a method for preparing amorphous molybdenum oxide adsorption material and an application thereof. The invention aims to solve the technical problem of low recovery efficiency of silver ions in coexisting silver-containing wastewater in the prior art. The method of the present invention includes:1) preparation of electrolyte; and 2) subjecting to cyclic voltammetry. The amorphous molybdenum oxide adsorption material prepared by the present invention is used as an adsorbent for adsorbing and reducing silver ions in wastewater. The invention successfully prepares amorphous molybdenum oxide (MoOx) by cyclic voltammetry, which has a highly selective reduction adsorption for Ag.sup.+. Silver ions and the adsorbent MoOx could be subjected to redox reaction to remove silver ions in water. The removal efficiency of the silver ions in wastewater by the amorphous molybdenum oxide prepared by cyclic voltammetry of the invention is up to 99.85%.

Claims

1. A method for preparing an amorphous molybdenum oxide adsorption material as an adsorbent for adsorbing and reducing silver ions, which is carried out by the following steps: 1) Preparation of an electrolyte: mixing ammonium molybdate and sodium sulfate together in water, and stirring ultrasonically for 5 min to 10 min to obtain a mixed solution, wherein in the mixed solution, the concentration of ammonium molybdate is 2 mmol/L to 2.5 mmol/L, and that of sodium sulfate is 0.5 mol/L to 0.6 mol/L; and 2) Subjecting to cyclic voltammetry: connecting an electrochemical workstation, and subjecting the mixed solution prepared in step 1) as the electrolyte to electrodeposition for 25 to 30 cycles by cyclic voltammetry to obtain the amorphous molybdenum oxide adsorption material, wherein the cyclic voltammetry has the potential window of −0.09 V to −1.29 V and the sweep speed of 50 mV/s to 60 mV/s.

2. The method of claim 1, wherein in the mixed solution in step 1), the concentration of ammonium molybdate is 2 mmol/L and that of sodium sulfate is 0.5 mol/L.

3. The method of claim 1, wherein in the electrochemical workstation in step 2) the working electrode is conductive glass ITO, the counter electrode is a platinum electrode, and the reference electrode is silver/silver chloride.

4. An application of the amorphous molybdenum oxide adsorption material of claim 1 as an adsorbent for adsorbing and reducing silver ions in wastewater.

5. The application of the amorphous molybdenum oxide adsorption material according to claim 4, wherein the application method comprises: putting the amorphous molybdenum oxide adsorption material as the adsorbent into silver ions-containing wastewater, and stirring for 5 h-5.5 h to adsorb silver ions completely.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a graph showing the removal efficiency of various metal ions in wastewater tested in Experiment 2.

(2) FIG. 2 shows a XRD diagram of the amorphous molybdenum oxide adsorption material prepared in Experiment 1.

(3) FIG. 3 shows a XRD diagram of working electrode loaded with amorphous molybdenum oxide adsorption material after absorbing silver ions tested in Experiment 2.

(4) FIG. 4 shows a SEM diagram of the amorphous molybdenum oxide adsorption material prepared in Experiment 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) The specific embodiment 1: A method for preparing amorphous molybdenum oxide adsorption material was carried out according to the following steps:

(6) 1) preparation of electrolyte: mixing ammonium molybdate and sodium sulfate together in water, and stirring ultrasonically for 5 min to 10 min to obtain a mixed solution, wherein in the mixed solution, the concentration of ammonium molybdate was 2 mmol/L to 2.5 mmol/L, and that of sodium sulfate was 0.5 mol/L to 0.6 mol/L; and

(7) 2) subjecting to cyclic voltammetry: connecting an electrochemical workstation, and subjecting the mixed solution prepared in step 1) as an electrolyte to electrodeposition for 25 to 30 cycles by cyclic voltammetry to obtain the amorphous molybdenum oxide adsorption material, wherein the cyclic voltammetry has the potential window of −0.09 V to −1.29 V and the sweep speed of 50 mV/s to 60 mV/s.

(8) The specific embodiment 2: The embodiment was different from the above embodiment 1 in that in the mixed solution in step 1), the concentration of ammonium molybdate was 2 mmol/L, and that of sodium sulfate was 0.5 mol/L. Others were the same as those in embodiment 1.

(9) The specific embodiment 3: The embodiment was different from the above embodiment 1 or 2 in that the electrochemical workstation in Step 2) has the model of CHI760E. Others were the same as those in embodiment 1 or 2.

(10) The specific embodiment 4: The embodiment was different from the above embodiment 3 in that in the electrochemical workstation in step 2), the working electrode was conductive glass ITO, the counter electrode was platinum electrode, and the reference electrode was silver/silver chloride. Others were the same as those in embodiment 3.

(11) The specific embodiment 5: The embodiment was an application of the amorphous molybdenum oxide adsorption material prepared in the specific embodiment 1 as an adsorbent for adsorbing and reducing silver ions in wastewater.

(12) The specific embodiment 6: The embodiment was different from the above embodiment 5 in the usage method of adsorbent: putting the adsorbent in wastewater and stirring for 5 h to 5.5 h to adsorb silver ions completely. Others were the same as those in embodiment 5.

(13) The following experiments were used to verify the present invention.

(14) Experiment 1: A method for preparing amorphous molybdenum oxide adsorption material was carried out according to the following steps:

(15) 1) preparation of electrolyte: mixing ammonium molybdate and sodium sulfate together in 100 ml of deionized water, and stirring ultrasonically for 10 min to obtain a mixed solution, wherein in the mixed solution, the concentration of ammonium molybdate was 2 mmol/L, and that of sodium sulfate was 0.5 mol/L; and

(16) 2) subjecting to cyclic voltammetry: connecting an electrochemical workstation, and subjecting the mixed solution prepared in step 1) as an electrolyte to electrodeposition for 25 cycles by cyclic voltammetry to obtain amorphous molybdenum oxide adsorption material, wherein the cyclic voltammetry has the potential window of −0.09 V to −1.29 V and the sweep speed of 50 mV/s.

(17) The electrochemical workstation in step 2) has the model of CHI760E, and in the workstation the working electrode was conductive glass ITO, the counter electrode was a platinum electrode, and the reference electrode was silver/silver chloride, wherein the conductive glass ITO has a size of 1 cm×4 cm×1.1 mm.

(18) Experiment 2: The working electrode located with amorphous molybdenum oxide adsorption material prepared in Experiment 1 was put into wastewater, and was stirred for 5 h-5.5 h to adsorb silver ions completely, wherein wastewater has the volume of 100 mL, and includes Ag.sup.+, CO.sup.2+, Ni.sup.2+, Cr.sup.3+, Cu.sup.2+ and Cd.sup.2+ in the concentrations of all 20 mg/L.

(19) FIG. 1 is a graph showing the removal efficiency of various metal ions in wastewater tested in Experiment 2. As can be seen from the figure, the amorphous molybdenum oxide MoOx prepared in the Experiment 1 exhibits good selectivity for silver ions and good removal efficiency for silver ions, up to 99.85%.

(20) FIG. 2 is a XRD diagram of the amorphous molybdenum oxide adsorption material prepared in Experiment 1. As can be seen from the figure, MoOx prepared in Experiment 1 is amorphous.

(21) FIG. 3 is a XRD diagram of the working electrode loaded with the amorphous molybdenum oxide adsorption material tested in Experiment 2, wherein curve a represents an actually measured curve, curved b represents a standard tin oxide, curve c represents a standard elementary substance Ag. As can be seen from the figure, the metallic Ag has been reduced.

(22) FIG. 4 is a SEM diagram of the amorphous molybdenum oxide adsorption material prepared in Experiment 1. As can be seen from the figure, the amorphous molybdenum oxide adsorption material has a sheet structure.