A novel and low-cost biosorbent of tea waste supported hydrous aluminium oxide (Tea-APAM-Al) was prepared with help of anionic polyacrylamide (APAM) for highly efficient defluoridation of drinking water. Batch adsorption studies were carried out by varying the adsorbent dosage, initial fluoride 10 concentration, contact time, initial pH, and presence of co-existing ions to evaluate the efficiency of fluoride removal. It was found that Tea-APAM-Al performed well over a considerably wide pH range, from 4.0-9.0. With the exception of bicarbonate, other co-existing ions (nitrate, chloride and sulphate) did not have significant effect on the defluoridation process. The adsorption process could be described by the Lagergern pseudo-second-order kinetic model. Adsorption data could be fitted by the Langmuir 15 isotherm model and the maximum fluoride adsorption capacity for Tea-APAM-Al was 42.14 mg/g. The results from SEM, EDS, XRD, FTIR and XPS studies showed that the fluoride adsorption mechanism likely involved hydroxyl and sulfate ion exchange with fluoride. Moreover, fluoride anion exchange with sulfate ions was the main mechanism for fluoride adsorption at low initial fluoride concentration.
Despite the high theoretical energy density, lithium–sulfur (Li–S) batteries are currently facing two major problems, i.e., the shuttle of polysulfides and sluggish redox kinetics.
In this paper a label-free fluorescent sensor for probing the interaction between heparin and protein was reported. Heparin, the bioactive polyanions, formed supramolecular assemblies with cationic surfactant cetyltrimethyl ammonium bromide (CTAB). The environment-dependent dye pyrene, encapsulated in hydrophobic interiors of the supramolecular assemblies worked as the fluorescence probe. Once the heparin-binding protein was added, competing interactions of protein with heparin would weaken the interaction between CTAB and heparin. As a result, the noncovalently sequestered pyrene would be released upon disassembly and the fluorescence of the released pyrene was subsequently decreased. The binding events were exemplified by protamine and Tat peptide, these processes were also verified by DLS and TEM. Such a strategy is appealing as organic synthesis was traded off against supramolecular assembly. This label-free fluorescent system is simple, selective, convenient, and can serve as a good complement to other existing methods, also this method has the potential for preprimary drug screening.
The chelating resin was synthesized by free-radical copolymerization of iminodiacetic acid modified glycidyl methacrylate with a cross-linker N,N′-methylene biscarylamide at 70°C for removal of heavy metal ions from aqueous solutions. The equilibrium adsorption capacities of the chelating resin from their single-metal ion solutions were 3.28 mmol/g for Cd(II), 2.36 mmol/g for Cu(II), 1.71 mmol/g for Mn(II), 1.69 mmol/g for Ni(II), 1.41 mmol/g for Zn(II), 1.24 mmol/g for Co(II), 0.78 mmol/g for Cr(III) and 0.66 mmol/g for Pb(II). Their related absorption behaviors are discussed in this paper such as thermodynamic equilibrium, pH effect and the Langmuir and Freundlich model to evaluate the experimental data. According to the results, this resin could be used as a promising adsorbent for industrial wastewater disposal.
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