The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, tr...The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, trans-membrane pressure and pretreatment time on the permeate concentration and permeate flux were studied. The results show that the necessary pretreatment time (NPT) increases with PAAS concentration, decreases with TMP. The change trend of permeate flux with time is affected by pH. The permeate fluxes rapidly decrease from the start, and then increase gradually to stable values at pH 5.0, pH 7.0 and pH 9.3. However, it decreases gradually with time till a state value at pH 3.0 (iso-electric point, IEP). The removal of small molecules is easy at pH greater than iso-electric point (IEP). The change of filtration potential with time indicates the similar trend to that of permeation concentration, but the former is more convenient for indication of NPT.展开更多
基金Projects(21176264,21476265)supported by the National Natural Science Foundation of China
文摘The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, trans-membrane pressure and pretreatment time on the permeate concentration and permeate flux were studied. The results show that the necessary pretreatment time (NPT) increases with PAAS concentration, decreases with TMP. The change trend of permeate flux with time is affected by pH. The permeate fluxes rapidly decrease from the start, and then increase gradually to stable values at pH 5.0, pH 7.0 and pH 9.3. However, it decreases gradually with time till a state value at pH 3.0 (iso-electric point, IEP). The removal of small molecules is easy at pH greater than iso-electric point (IEP). The change of filtration potential with time indicates the similar trend to that of permeation concentration, but the former is more convenient for indication of NPT.
