| Adsorbent resin NDA-150 and PS-SA were prepared by post-crosslinking of chloromethylatead PS-DVB and chemical modification reaction. The structure and surface parameters of NDA150, PS-SA and commercially available adsorbent resin XAD-4 were characterized using Fourier transform infrared spectroscopy(FTIR),specific surface area analyzer(BET and BJH) and scanning electron microscopy(SEM), and thermal gravimetric analysis methods. The isothermal adsorption experiments studied the adsorption properties and mechanism for single-component and two-component adsorbate. The results show:(1) XAD-4, NDA150 and PS-SA resin were all based on a polystyrene-diethylene benzene skeleton. Comparison of the micro-pore structure and the specific surface area of the three resins indicated: NDA150> PS-SA> XAD-4, and all of the three resins had a high thermal stability.(2) In the experimental temperature range, single-component adsorption experiments of 2-naphthol, 1-naphthylamine, salicylic acid and naphthalene on NDA150 and XAD-4 were studied. Adsorption isotherms of 2-naphthol,1-naphthylamine and salicylic acid all fitted Langmuir model, and belonged to monolayer adsorption and thermopositive reaction. While adsorption isotherms of Naphthalene on NDA150 and XAD-4 fitted Freundlich isotherm model and DR isotherm model. NDA150 had a higher adsorption capacity for 2-naphthol,1-naphthylamine, salicylic acid and naphthalene than XAD-4.( 3) Two-component adsorption experiments of NDA150 and XAD-4 for2-naphthol and 1-naphthylamine 、 2-naphthol and salicylic acid indicated that the adsorption capacity in two-component adsorption experiments was less than that in single-component ones. But the total adsorbance in two-component adsorption experiments was higher than each of the single-component adsorbances under the same equilibrium concentration. Adsorption experiments of naphthalene coexisting with polar organic compounds(salicylic acid, 2-naphthol) showed that low concentration of polar organic compounds had no significant effect on the naphthalene adsorption. With the concentration increase of polar organics, more significant inhibition of naphthalene adsorption was found.(4) Extended Freundlich model well described two-component competitive adsorption behavior of 2-naphthol and 1-naphthylamine, 2-naphthol and salicylic acid,naphthalene and salicylic acid on NDA150 and XAD-4 resins; Modified Langmuirmodel fitted two-component competitive adsorption behavior of naphthalene and1-naphthylamine on the resins.(5) Cu2+ and Pb2+ adsorptions on PS-SA and NDA150 were thermopositive process, during which PS-SA had a higher adsorption capacity of Cu2+ and Pb2+ than NDA150, and both PS-SA and NDA150 had a higher adsorption capacity of Pb2+ than Cu2+. Adsorption experiments of 2-naphthol, 1-naphthylamine and salicylic acid on PS-SA and NDA150 were thermopositive. NDA150 had a higher adsorption capacity of all three aromatic compounds than PS-SA. Adsorption capacities of the three aromatic compounds ranked as: 1-naphthylamine> 2-naphthol> salicylic acid.(6) Experiments regarding the influence of aromatic compounds on Cu2+, Pb2+adsorption on NDA150 and PS-SA indicated the process as thermopositive and accordant to the Langmuir model, which belonged to monolayer adsorption. Higher concentration of aromatic compounds led to lower adsorbance of Cu2+ and Pb2+ on NDA150 and PS-SA. Effects of the three aromatic compounds on the resin adsorption of Cu2+ and Pb2+ varied in that resin adsorbances of Cu2+ and Pb2+ ranked as:1-Naphthylamine + Cu2+, Pb2+<2- naphthol + Cu2+, Pb2+<salicylate + Cu2+, Pb2+.(7) Experiments regarding the influences of Cu2+, Pb2+ on aromatic compounds adsorption on NDA150 and PS-SA found the processes as thermopositive, and accordant to the Langmuir model, which belonged to monolayer adsorption. Higher concentration of heavy metals led to weaker attraction force of aromatic compounds on the resins thus the decrease of adsorption capacity. |
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