Flocculation Performance Of Extracting Solution From Pineapple Peel

In this paper,pineapple peel was used as raw material to study the extracting conditions of pineapple peel extracting solutiont(PAP),and the effect of dilution on the stability of PAP flocculation performance was studied.PAP was compared with that of hybrid peel(HFP)flocculant in treating simulated humic acid water and simulated domestic sewage.And the PAP was characterized by scanning electron microscopy(SEM),fourier transforrosm infrared spectroscopy(FTIR),and nanoparticle size analyzer.Finally,the flocculation mechanism of PAP was analyzed.(1)Through single factor and orthogonal experiments,the extracting conditions of PAP were determined as follows: solid-liquid ratio 1:20,extraction temperature 70 ℃ and the extraction time 20 min.(2)Dilution can greatly improve the stability of PAP.With the increase of storage time,the flocculation effect of PAP and diluted 2 times PAP showed a downward trend.The removal effect of diluted 4 times PAP on humic acid simulated water remained basically stable,and the treatment effect of domestic sewage decreased rapidly after 15 days.The turbidity removal rate and color removal rate of the two kinds of simulated water were basically stable with the 10-fold dilution of PAP.The p H of PAP and the diluent both changed from alkaline to acidic as time increased.PAP had a wall hanging phenomenon at 2d,while the other three had no obvious changes in appearance.At 15 d,the color of the diluted solution became lighter,and different amounts of white flocs were produced with sour taste.During a certain storage period,microorganisms in PAP may participate in flocculation.(3)The process conditions for PAP treatment of simulated humic acid water and simulated domestic sewage were determined through orthogonal experiments: the speed of fast stirring was 400 r/min,the time of fast stirring was 2 min,and the gradient of slow stirring was 80 r/min for 8 min,40 r/min,4 min and 80 r/min for 7 min,40 r/min for 3 min.In the experiment of treating humic acid simulated water,when the optimal dosage of PAP was30 mg/L,not only the removal effect of turbidity and chroma was better,but also the content of organic matter entering the water body was less.And the p H adaptation range of pap was4～ 8,it was not as adaptable as HFP in the removal of turbidity.In the experiment of treating simulated domestic sewage,when the optimal dosage of PAP was 60 mg/L,the removal rate of turbidity and color can reach 95.90% and 93.11% respectively.For the removal of COD,both PAP and HFP showed a fluctuating downward trend as the dosage increases.The removal rate of phosphorus by PAP and HFP was below 10%.The removal effect of PAP and HFP on turbidity and chroma was better at p H 3～11,but if COD is taken into account,the preferred p H range of PAP is 7-11.The flocs formed by PAP and HFP had excellent settling performance,and most of the flocs had settled in 3 minutes,so PAP and HFP were suitable as fast flocculants.(4)PAP is rich in sugar,accounting for about 90% of its total organic carbon content.The ingredients are rich in-OH,-COOH and other functional groups,which have negative charge.The flocculation mechanism of PAP is mainly adsorption bridging,and the active groups in the molecular chain adsorb colloidal particles through van der Waals forces,hydrogen bonds and other forces.At the same time,it has a certain degree of net-repairing and sweeping effect.