Iron-manganese composited oxide（FeMnO） was prepared with potassium permanganate and ferrous salt. Interface performance, charge property and structure topography of the FeMnO were investigated. Coagulation efficienc...Iron-manganese composited oxide（FeMnO） was prepared with potassium permanganate and ferrous salt. Interface performance, charge property and structure topography of the FeMnO were investigated. Coagulation efficiency and pollution removal mechanism of the FeMnO were approached. Results show that the main compositions of the FeMnO are δ-manganese dioxide and ferric hydroxide. The specific surface area is about 146.22 m^2/g. The FeMnO contains rich hydroxyl with extremely strong adsorption action and chemical adsorption activity. The zero charge point of the oxide in pure water is about 8.0 of pH value. Under neutral pH value conditions, the FeMnO particle surface carried positive charges. The FeMnO particles are quasi-spherical micro-particles with irregular sizes adjoined each other to form net construction. Phosphorus removal efficiency of the FeMnO is remarkable, the total dissoluble phosphorus of settled water can be reduced below detecting level（0.3 μtg/L） at a FeMnO dosage of 6 mg/L, and total phosphorus below detecting level at a FeMnO dosage of 10 mg/L, for water samples containing total phos- phorus of 1281.70 μg/L and total dissoluble phosphorus of 1187.91 μtg/L. The mechanism of effective coagulation for phosphorus removal is combined results of multiple actions of adsorption, charge neutralization, adsorption/bridging and so on.展开更多
This work studied the structural effects of hematite(α-Fe2 O3), 2-line ferrihydrite(HFO) and goethite(α-FeOOH) on diethyl phthalate ester(DEP) degradation. The results showed that the degradation of DEP was faster u...This work studied the structural effects of hematite(α-Fe2 O3), 2-line ferrihydrite(HFO) and goethite(α-FeOOH) on diethyl phthalate ester(DEP) degradation. The results showed that the degradation of DEP was faster under 365 nm light irradiation than in the dark in the presence of iron(hydr)oxides. The apparent kinetic rates of DEP degradation followed the order HFO > goethite ≈ hematite in the dark and HFO > hematite > goethite under 365 nm light irradiation. Two pathways governed H2 O2 decomposition efficiency on iron(hydr)oxide surfaces:(1) forming UOH on inherent surface hydroxyl groups(Fe-OH) and(2) producing O2 and H2 O on the surface oxygen vacancies. X-ray photoelectron spectroscopy(XPS) analyses indicated that HFO not only has high Fe-OH content but also has high Vo content, resulting in its low H2 O2 utilization efficiency(η). DEP was degraded through hydrogen abstraction and deesterification, and the major products were(OH)2-DEP, mono-ethyl phthalate(MEP), OH-MEP,and phthalate acid(PA). The study is important in understanding the transformation of phthalate esters in top surface soils and surface waters under ultraviolet light.展开更多
The development of biochar-based granule-like adsorbents suitable for scaled-up application has been attracting increasing attention in the field of water treatment.Herein,a new formable porous granulated biochar load...The development of biochar-based granule-like adsorbents suitable for scaled-up application has been attracting increasing attention in the field of water treatment.Herein,a new formable porous granulated biochar loaded with La-Fe(hydr)oxides/montmorillonite(LaFe/MB)was fabricated via a granulation and pyrolysis process for enhanced phosphorus(P)removal from wastewater.Montmorillonite acted as a binder that increased the size of the granulated biochar,while the use of Fe promoted the surface charge and facilitated the dispersion of La,which was responsible for selective phosphate removal.LaFe/MB exhibited rapid phosphate adsorption kinetics and a high maximum adsorption capacity(Langmuir model,52.12 mg P g^(−1)),which were better than those of many existing granulated materials.The desorption and recyclability experiments showed that LaFe/MB could be regenerated,and maintained 76.7%of its initial phosphate adsorption capacity after four adsorption cycles.The high hydraulic endurance strength retention rate of the developed material(91.6%)suggested high practical applicability in actual wastewater.Electro-static attraction,surface precipitation,and inner-sphere complexation via ligand exchange were found to be involved in selective P removal over a wide pH range of 3-9.The thermodynamic parameters were determined,which revealed the feasibility and spontaneity of adsorption.Based on approximate site energy distribution analyses,high distribution frequency contributed to efficient P removal.The research results provide a new insight that LaFe/MB shows great application prospects for advanced phosphate removal from wastewater.展开更多
A1-Fe （hydr）oxides with different A1/Fe molar ratios （4：1, 1：1, 1：4, 0：1） were prepared using a co- precipitation method and were then employed for simultaneous removal of arsenate and fluoride. The 4A1 ： Fe ...A1-Fe （hydr）oxides with different A1/Fe molar ratios （4：1, 1：1, 1：4, 0：1） were prepared using a co- precipitation method and were then employed for simultaneous removal of arsenate and fluoride. The 4A1 ： Fe was superior to other adsorbents for removal of arsenate and fluoride in the pH range of 5.0-9.0. The adsorption capacity of the A1-Fe （hydr）oxides for arsenate and fluoride at pH 6.50.3 increased with increasing A1 content in the adsorbents. The linear relationship between the amount of OH released from the adsorbent and the amount of arsenate or fluoride adsorbent by 4A1 ： Fe indicated that the adsorption of arsenate and fluoride by A1- Fe （hydr）oxides was realized primarily through quantita- tive ligand exchange. Moreover, there was a very good correlation between the surface hydroxyl group densities of A1-Fe （hydr）oxides and their adsorption capacities for arsenate or fluoride. The highest adsorption capacity for arsenate and fluoride by 4A1 ： Fe is mainly ascribed to its highest surface hydroxyl group density besides its largest pHpzc. The dosage of adsorbent necessary to remove arsenate and fluoride to meet the drinking water standard was mainly determined by the presence of fluoride since fluoride was generally present in groundwater at much higher concentration than arsenate.展开更多
In this paper, a series of Fe- and Co-doped lanthanum（hydr）oxides catalysts were prepared by a simple coprecipitationhydrothermal method. The as-prepared catalysts were characterized with various techniques includin...In this paper, a series of Fe- and Co-doped lanthanum（hydr）oxides catalysts were prepared by a simple coprecipitationhydrothermal method. The as-prepared catalysts were characterized with various techniques including powder X-ray diffraction（XRD）, N2 adsorption/desorption, inductively coupled plasma（ICP） and transmission electron microscopy（TEM）. The Fe-based catalysts exhibited consecutive phase changes of amorphous Fe Ox→FeLaO3→Fe2N under different stages（as-prepared→calcination→ammonia decomposition reaction）; as for Co-based catalysts, the phase transformation followed a sequence of Co（OH）2→Co3O4→metallic Co. It was revealed that Fe2N and metallic Co were most probably the active crystalline phase respectively for Feand Co-based catalysts in the decomposition of ammonia.展开更多
基金Supported by National Natural Science Foundation of China(Nos.50378004 and 50678007)Beijing Natural Science Foun-dation(No.8082009)+1 种基金Science & Technology Development Programme of Beijing Municipal Commission of Education (No.KM200610005025)Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality(No. 05004014200701).
文摘Iron-manganese composited oxide（FeMnO） was prepared with potassium permanganate and ferrous salt. Interface performance, charge property and structure topography of the FeMnO were investigated. Coagulation efficiency and pollution removal mechanism of the FeMnO were approached. Results show that the main compositions of the FeMnO are δ-manganese dioxide and ferric hydroxide. The specific surface area is about 146.22 m^2/g. The FeMnO contains rich hydroxyl with extremely strong adsorption action and chemical adsorption activity. The zero charge point of the oxide in pure water is about 8.0 of pH value. Under neutral pH value conditions, the FeMnO particle surface carried positive charges. The FeMnO particles are quasi-spherical micro-particles with irregular sizes adjoined each other to form net construction. Phosphorus removal efficiency of the FeMnO is remarkable, the total dissoluble phosphorus of settled water can be reduced below detecting level（0.3 μtg/L） at a FeMnO dosage of 6 mg/L, and total phosphorus below detecting level at a FeMnO dosage of 10 mg/L, for water samples containing total phos- phorus of 1281.70 μg/L and total dissoluble phosphorus of 1187.91 μtg/L. The mechanism of effective coagulation for phosphorus removal is combined results of multiple actions of adsorption, charge neutralization, adsorption/bridging and so on.
基金funded by the National Natural Science Foundation of China (No. 41773125)the Research Instrument Development Program of Chinese Academy of Sciences (No. YZ201638)the 135 Research Program of the Chinese Academy of Sciences (No. ISSASIP1620)
文摘This work studied the structural effects of hematite(α-Fe2 O3), 2-line ferrihydrite(HFO) and goethite(α-FeOOH) on diethyl phthalate ester(DEP) degradation. The results showed that the degradation of DEP was faster under 365 nm light irradiation than in the dark in the presence of iron(hydr)oxides. The apparent kinetic rates of DEP degradation followed the order HFO > goethite ≈ hematite in the dark and HFO > hematite > goethite under 365 nm light irradiation. Two pathways governed H2 O2 decomposition efficiency on iron(hydr)oxide surfaces:(1) forming UOH on inherent surface hydroxyl groups(Fe-OH) and(2) producing O2 and H2 O on the surface oxygen vacancies. X-ray photoelectron spectroscopy(XPS) analyses indicated that HFO not only has high Fe-OH content but also has high Vo content, resulting in its low H2 O2 utilization efficiency(η). DEP was degraded through hydrogen abstraction and deesterification, and the major products were(OH)2-DEP, mono-ethyl phthalate(MEP), OH-MEP,and phthalate acid(PA). The study is important in understanding the transformation of phthalate esters in top surface soils and surface waters under ultraviolet light.
基金National Key Research and Development Program of China(2021YFD1700805)National Natural Science Foundation of China(41807132,22078136,41877090)the Jiangsu Province Agricultural Independent Innovation Fund(CX(19)2003).
文摘The development of biochar-based granule-like adsorbents suitable for scaled-up application has been attracting increasing attention in the field of water treatment.Herein,a new formable porous granulated biochar loaded with La-Fe(hydr)oxides/montmorillonite(LaFe/MB)was fabricated via a granulation and pyrolysis process for enhanced phosphorus(P)removal from wastewater.Montmorillonite acted as a binder that increased the size of the granulated biochar,while the use of Fe promoted the surface charge and facilitated the dispersion of La,which was responsible for selective phosphate removal.LaFe/MB exhibited rapid phosphate adsorption kinetics and a high maximum adsorption capacity(Langmuir model,52.12 mg P g^(−1)),which were better than those of many existing granulated materials.The desorption and recyclability experiments showed that LaFe/MB could be regenerated,and maintained 76.7%of its initial phosphate adsorption capacity after four adsorption cycles.The high hydraulic endurance strength retention rate of the developed material(91.6%)suggested high practical applicability in actual wastewater.Electro-static attraction,surface precipitation,and inner-sphere complexation via ligand exchange were found to be involved in selective P removal over a wide pH range of 3-9.The thermodynamic parameters were determined,which revealed the feasibility and spontaneity of adsorption.Based on approximate site energy distribution analyses,high distribution frequency contributed to efficient P removal.The research results provide a new insight that LaFe/MB shows great application prospects for advanced phosphate removal from wastewater.
文摘A1-Fe （hydr）oxides with different A1/Fe molar ratios （4：1, 1：1, 1：4, 0：1） were prepared using a co- precipitation method and were then employed for simultaneous removal of arsenate and fluoride. The 4A1 ： Fe was superior to other adsorbents for removal of arsenate and fluoride in the pH range of 5.0-9.0. The adsorption capacity of the A1-Fe （hydr）oxides for arsenate and fluoride at pH 6.50.3 increased with increasing A1 content in the adsorbents. The linear relationship between the amount of OH released from the adsorbent and the amount of arsenate or fluoride adsorbent by 4A1 ： Fe indicated that the adsorption of arsenate and fluoride by A1- Fe （hydr）oxides was realized primarily through quantita- tive ligand exchange. Moreover, there was a very good correlation between the surface hydroxyl group densities of A1-Fe （hydr）oxides and their adsorption capacities for arsenate or fluoride. The highest adsorption capacity for arsenate and fluoride by 4A1 ： Fe is mainly ascribed to its highest surface hydroxyl group density besides its largest pHpzc. The dosage of adsorbent necessary to remove arsenate and fluoride to meet the drinking water standard was mainly determined by the presence of fluoride since fluoride was generally present in groundwater at much higher concentration than arsenate.
基金Project supported by the National Natural Science Foundation of China(21301107,21501109)Fundamental Research Funding of Shandong University(2014JC005)+1 种基金the Taishan Scholar Project of Shandong Province(China)Doctoral Funding of Ministry of Education of China(20130131120009)
文摘In this paper, a series of Fe- and Co-doped lanthanum（hydr）oxides catalysts were prepared by a simple coprecipitationhydrothermal method. The as-prepared catalysts were characterized with various techniques including powder X-ray diffraction（XRD）, N2 adsorption/desorption, inductively coupled plasma（ICP） and transmission electron microscopy（TEM）. The Fe-based catalysts exhibited consecutive phase changes of amorphous Fe Ox→FeLaO3→Fe2N under different stages（as-prepared→calcination→ammonia decomposition reaction）; as for Co-based catalysts, the phase transformation followed a sequence of Co（OH）2→Co3O4→metallic Co. It was revealed that Fe2N and metallic Co were most probably the active crystalline phase respectively for Feand Co-based catalysts in the decomposition of ammonia.
