A high-efficient monoclinic BiVO 4 adsorbent for selective capture toxic selenite

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1 Supporting Online Materials for A high-efficient monoclinic BiVO 4 adsorbent for selective capture toxic selenite Huan Ouyang, Yuanyuan Sun*, and Jianqiang Yu* Collaborative Innovation Center for Marine Biomass Fibers Materials and Textiles of Shandong Province, School of Environmental Science and Engineering, Qingdao University, Qingdao , P. R. China. Experimental materials and methods The Preparation of ms-bivo 4.The ms-bivo 4 was prepared following the methods reported in the literature. 1 The synthesis was carried out under hydrothermalconditions in 100 ml Teflon lined steel reactor. In a typical synthesis, theprecursors Bi(NO 3 ) 3 5H 2 O (50 mmol) and NH 4 VO 3 (50 mmol)were dissolved in 10 ml of 4.0 M HNO 3 solution and 10 ml2.0 M NaOH solution, respectively. After stirring for 0.5 h, the suspensionwas transferred into a Teflon-lined stainless steel autoclave, and reacted at 150 C for 12 h.after hydrothermal reaction, the precipitate was washed andcentrifuged in deionized water three times, and finally driedovernight at 60 C. Preparation of selenium solutions. All the Selenium Solutions were prepared by dissolved Na 2 SeO 3 into UP water to form the corresponding concentrations. Characterizations. X-ray diffraction (XRD) was implemented by DX2700 (Dandong, China) operating with voltage 40 kv and current 30 ma equipped by Cu Kα radiation (λ = Å). The morphology and structure of the samples were investigated by using a field emission scanning electron microscope (FESEM, JSM-7001F, JEOL, Tokyo, Japan). The specific surface area was calculated by the Brunauer-Emmett-Teller (BET) method with a relative pressure (P/P 0 ) range between and The pore size distribution plots were derived from the adsorption branch of the isotherms based on the BJH model. The chemical constitution was investigated by X-ray photoelectron spectroscopy (XPS) using an ESCALab250 electron spectrometer (Thermo Scientific Corporation) with monochromatic 150 W Al Kα radiation. The concentration of selenium in the aqueous solution was analyzed by atomic absorption spectrophotometer (AAS) technique using a PGENERAL TAS-986. Equilibrium adsorption test.the equilibrium uptake studies was carried out under a series of concentrations of Se solutions ranging from 1 ppm to 300 ppm with 0.5 mg/ml adsorbent in a glass tube. And all the SeO 2 3 solutions with adsorbent were under magnetic stirring for 48 h at room temperature. After equilibrium time, the solids and solutions were separated by filtering and the remaining solution were analyzed by an AAS to confirm the concentration of selenium in the

2 solutions. The following experiment's result analyzing and the treatment of solids and solutions are the same. Kinetic adsorption test.kinetic adsorption studies were performed by using 0.5 mg/ml ms-bivo 4 to an aqueous, 100 ppm solution of selenium in a glass tube. The influence of ph on SeO 2-3 adsorption.the effect of solution's ph on SeO 2 3 adsorption was evaluated in the range of ph The experiments were done by adjusting the ph of 100 ppm solution of selenium with CH 3 COOH (0.001 M) and NH 4 OH (0.001 M) solutions, while the original ph of selenium solution is Competitive adsorption.the competitive uptake of SeO 2 3 by ms-bivo 4 adsorbent was investigated under the environment with high concentrations (10 4 ppm) co-existing anions. In this study, 8 types of oxyanions (NO 3, NO 2, Br, HCO 3, Cl, Ac, SO 2 4, and CO 2 3 ) were individually added into an aqueous mixture solution containing 5 ppm selenium and 0.5 mg/ml ms-bivo 4 adsorbent. Desorption experiment. Desorption experiments were carried out at room temperature. The specific detail is putting 10 mg samples which were reached the adsorption equilibrium into 20 ml H 2 O under magnetic stirring. Testing the SeO 2 3 concentration at different times. Results and Discussion XPS spectra analysis.the XPS was carried out to identify the composition and chemical state of the atoms in the samples. Before adsorption of SeO 2 3 anions, the O 1s core level spectrum perfectly fitted well with three peaks (Figure S6b). The peak at ev and ev which corresponded to the O 2 anions in ms-bivo 4. And the other peak at ev is attributed to the chemisorbed H 2 O or OH on the surface. The peaks at (V 2p1/2) and ev (V 2p3/2) in ms-bivo 4 were the splitting signals of V2p, ascribed to the V 5+ species, which indicated that the element V in ms-bivo 4 was in pentavalent state(figure S6c).The splitting signals at ev and ev were the characteristic peaks of Bi 4f 7/2and Bi 4f5/2which indicated that Bi existed in form of Bi 3+ in ms-bivo 4 (Figure S6d).

3 Figures Figure S1. X-ray diffraction pattern of synthesized ms-bivo 4 compared to ms-bivo 4 in UP water. Figure S2. SEM image of ms-bivo 4 in UP water.

4 Figure S3. Nitrogen adsorption isotherm of ms-bivo 4 in UP water. Figure S4.Pore size distributions of ms-bivo 4 in UP water.

5 Figure S5.The desorption rate of ms-bivo 4 -SeO 3 2. Figure S6.XPS spectra of ms-bivo 4 adsorbent before adsorption of SeO 3 2 : (a) survey scan, (b) O 1s, (c) V 2p (d) Bi 4f of ms-bivo 4.

6 Table S1. Maximum Adsorption Capacity of Different Adsorbents Including ms-bivo 4 Adsorbent Selenite Capacity (mg/g) Reference ms-bivo This work Fe 3 O microspheres Aluminum Oxide in Chitosan Beads Nano-Hematite Fe 3 O 4 Nanoparticles Mercapto-silica Chitosan-clay composites Al2O3 Chitosan-clay composites Fe2O Chitosan-clay

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