New insights into membrane fouling in coagulation-ultrafiltration by cake characteristics analysis:A case study with PACl-Al_(13)and PACl

Membrane fouling is a bottleneck issue that hindered the further application of ultrafiltration technology.To alleviate membrane fouling,coagulation-ultrafiltration(C-UF)process using polyaluminum chloride(PACl)and PACl-Al_(13)with high proportion of Al_(13)O_(4)(OH)_(24)^(7+)as coagulants,respectively,were investigated at various pH conditions.Results indicated that an increase in solution pH contributed to larger floc size and looser floc structure for both PACl and PACl-Al_(13).It was conducive to the formation of more porous cake,as evidenced by mean pore area and pore area distribution of cake,leading to lower reversible fouling.Furthermore,humic acid(HA)removal presented a trend of first increasing and then decreasing with the increase of pH.The optimal HA removal was achieved at pH 6 regardless of coagulant type,suggesting that the slightest irreversible fouling should be occurred at this point.Interestingly,the irreversible fouling with PACl coagulant achieved a minimum value at pH 9,while the minimal irreversible fouling with PACl-Al_(13)was observed at pH 6.We speculated that the cake formed by PACl could further intercept HA prior to UF process at alkaline pH.Furthermore,compared with PACl,PACl-Al_(13)had a stronger charge neutralization ability,thus contributing to more compact floc structure and higher HA removal at various pH conditions.By UF fractionation measurement,higher HA removal for PACl-Al_(13)was due to higher removal of HA with molecular weight less than 50 kDa.

Preliminary study of application effect of bamboo vinegar on vegetable growth

Tiffs paper reports the effects of moso bamboo （Phyllostachys pubescense） vinegar, with different diluents, on the growth of lettuce, cole and cucumber based on field tests. The results show that moso bamboo vinegar with 500-800 times dilution had good effect on the growth of tested vegetables. The harvest of vegetables increased from 18.8%-20.2% compared with a control. The height and the weight of the average single vegetable tested also increased. The main components of moso bamboo vinegar were analyzed by GC-MS and the positive effect on the growth was, in the first instance, attributed to a synergistic effect of trace amounts of the main components of bamboo vinegar.

A novel insight of degradation ibuprofen in aqueous by catalytic ozonation with supported catalyst:Supports effect on ozone mass transfer

Catalytic ozonation is an effective wastewater purification process.However,the low ozone mass transfer in packed bubble columns leads to low ozone utilization efficiency(OUE),poor organic degradation performance,and high energy consumption.Therefore,there is an urgent need to develop efficient supported catalysts that can enhancemass transfer and performance.However,the reaction mechanism of the support on ozone mass transfer remains unclear,which hinders the development of catalytic ozonation applications.In this study,lava rocks(LR)-supported catalysts,specifically CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR,were proposed for catalytic ozonation of IBP degradation due to their superior catalytic activity,stability,and high OUE.Addition of CuMn_(2)O_(4)@LR or MnO_(2)–Co_(3)O_(4)@LR increased IBP removal efficiency from 85%to 91%or 88%,and reduced energy consumption from 2.86 to 2.14 kWh/m^(3)or 2.60 kWh/m^(3),respectively.This improvement was attributed to LRsupported catalysts enhancing mass transfer and promoting O3 decomposition to generate•OH and•O_(2)^(−),leading to IBP degradation.Furthermore,this study investigated the effects of ozone dose,supporter sizes,and catalyst components on ozone-liquid mass transfer.The results revealed that the size of the supporter influenced stacked porosity and consequently affected ozone mass transfer.Larger-sized LR(kLa=0.172 min^(−1))exhibited better mass transfer compared to smaller-sized supports.Based on these findings,it was concluded that both CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR are potential catalysts for catalytic ozonation in residual IBP degradation of pharmaceutical wastewater,and LR showed good credibility as a catalyst supporter.Understanding the effects of supporters and active components on ozone mass transfer provides a fundamental principle for designing supported catalysts in catalytic ozonation applications.