- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Highly efficient removal of phosphonates from water by a combined Fe(III)/UV/co-precipitation process
摘要： Considerable amount of phosphorous is present as organic phosphonates (usually in the form of metal complexes, e.g., Ca(II)-phosphonate) in domestic and industrial effluents, which cannot be effectively removed by traditional processes for phosphate. Herein, we employed a proprietary process, i.e., Fe(III) displacement/UV irradiation/co-precipitation (denoted Fe(III)/UV/NaOH), to enable an efficient removal of Ca(II)-phosphonate complexes from water. The combined process includes three basic steps, i.e., Fe(III) replacement with the complexed Ca(II) to form Fe(III)-phosphonate of high photo-reactivity, UV-mediated degradation of Fe(III)-phosphonate to form phosphate and other intermediates, and the final phosphorous removal via co-precipitation at pH=6. The operational conditions for the combined process to remove a typical phosphonate Ca(II)-NTMP (nitrilotrismethylenephosphonate) are optimized, where ~60% NTMP is transformed to phosphate with the total phosphorous reduction from 1.81 mg/L to 0.17 mg/L. Under UV irradiation, the cleavage of NTMP is identified at the C-N and C-P bonds to form the intermediate products and phosphate in sequence. Also, the combined process is employed for treatment of two authentic effluents before and after activated sludge treatment, resulting in the phosphorous drop from 4.3 mg/L to 0.23 mg/L and from 0.90 mg/L to 0.14 mg/L respectively, which is much superior to other processes including Fenton/co-precipitation. In general, the combined process exhibits great potential for efficient removal of phosphonates from contaminated waters.
关键词： Photolysis,Fe(III) replacement,Advanced treatment,Phosphonates
更新于2025-09-23 15:22:29
-
Two Highly Stable Luminescent Lead Phosphonates Based on Mixed Ligands: Highly Selective and Sensitive Sensing for Thymine Molecule and VO <sub/>3</sub><sup>–</sup> Anion
摘要： Two luminescent lead phosphonates with two-dimensional (2D) layer and three-dimensional (3D) framework structure, namely, Pb3[(L1)2(Hssc)(H2O)2] (1) and [Pb2(L2)0.5(bts)(H2O)2]·H2O (2) (H2L1 = O(CH2CH2)2NCH2PO3H2, H4L2 = H2PO3CH2NH(C2H4)2NHCH2PO3H2, H3ssc = 5-sulfosalicylic acid, NaH2bts = 5-sulfoisophthalic acid sodium) have been prepared via hydrothermal techniques. The two compounds not only show excellent thermal stability but also remain intact in aqueous solution within an extensive pH range. Moreover, the atomic absorption spectroscopy analysis experiment indicates that there does not exist the leaching of Pb2+ ions from the lead phosphonates, which show they are nontoxic in aqueous solution. In compound 1, the Pb(1)O4, Pb(2)O7, Pb(3)O4, and CPO3 polyhedra are interlinked into a one-dimensional chain, which is further connected to adjacent chain by sharing the Hssc2? to form a 2D layer. Interestingly, compound 1 as a highly selective and sensitive luminescent material can be used to detect the thymine molecule with a very low detection limit of 8.26 × 10?7 M. In compound 2, the Pb(1)O6 and Pb(2)O5 polyhedra are interlinked into a dimer via edge sharing, which is further connected to adjacent dimer to form a tetramer via corner sharing, and such a tetramer is then interlinked into a 2D layer through bts3? ligands; the adjacent 2D layers are finally constructed to a 3D structure by sharing the L24? ligand. Compound 2 can be applied as an excellent luminescent sensor for sensing of VO3? anion. Furthermore, the probable fluorescent quenching mechanisms of the two compounds have also been studied.
关键词： chemical stability,luminescent lead phosphonates,VO3? anion,thermal stability,hydrothermal techniques,fluorescent quenching mechanisms,thymine molecule
更新于2025-09-10 09:29:36
-
Phosphorus and Silicon Containing Inorganic Polymers. Poly(dimethylsilane H-phosphonate): Synthesis and NMR Characterization
摘要： In this paper we have demonstrated a new synthetic approach to a phosphorus and silicon containing inorganic polymer with a chain structure [-O-P(O)(H)-O-Si(CH3)2-]. It has been obtained from dichlorodimethylsilane and dimethyl ester of H-phosphonic acid taken in excess via catalyst and solvent free process, performed in two stages. The first one involved dealkylation reaction which was favoured by the nucleophilic attack of the chlorine atoms from the silane derivative at the α–carbon atoms of the dialkyl H-phosphonate. At the second polycondensation stage the molecular mass of the product increased. In the present study dimethyl H-phosphonate and dichlorodimethylsilane were used at a molar ratio 1.3:1 and the process was carried out at temperature up to 65 °C. The structure of the new polymer was proved by multinuclear NMR spectroscopy in solution and solid state. The thermal properties of the polymer product were measured.
关键词： silanes,inorganic polymers,NMR spectroscopy,copolymerization,phosphonates
更新于2025-09-04 15:30:14