Removal Efficiencies Of Pentachlorophenol And Disperse Red3B Onto Biochars From Aqueous Solution

Pentachlorophenol(PCP),which is chemically stable and resistants to degradation,has produced importantinfluence on the environment and human health. PCP has beenwidely used asherbicides and pesticidesfor a long time in China and remains in water,soils, organisms, etc. With the development of printing and dyeing industry, a largeamount of printing and dyeing wastewater is discharged into the river each year.Printing anddyeing wastewateris an industrial effluent that is difficult to be disposed,due to its high quantity, complex composition,high chroma, high toxicityetc. Toachieve a rational and efficient use of natural resources and control environmentpollution with different types of organic pollutants,biochar has beenwidely used toremove PCP and dye from water with high effectiveness and at low cost, because ofthe wide raw materialsourcesand strong adsorption. It is significant to adapt to thedevelopment pattern in new-era and promote environmentally sustainable growth andnature resources circulation.In the paper, we chose reeds, wheat straw and peanut shell to prepare biocharsand studiedtheir physical and chemical properties. The process of removal PCP anddisperse dyes from water was explored further.Main results for this study were asfollows:(1) Carbonization temperature had a significant impact on the elementalcompositionand structure elements biochars.With the carbonization temperature raised, theorganic matter of carbonization production gradually reduced, pore structuregradually developed.While the carbon content increased, hydrogen and oxygencontent decreased,the aromaticity gradually increased, and the polarity decreased.(2) Two organic pollutants (PCP and disperse red3B)in water were removedeffectively by all three biochars.Carbonization temperature had great influence onthe adsorption properties of three different biochars, which followed the order:H400>H600>H500>H300,X400>X600>X500>X300andL600>L500>L400.Among three biochars produced from different materials, Manifested as reed biocharhasthe best performance of adsorption, followed by peanut shells biochar and wheatstraw biochar, respectively. (3) Removal efficiency wassignificantly affected by addition amount. The removalrate of organic pollutants in waterincreased with rising addition.With regard to pH,the removal efficiency of biochar for PCPdecreased with the increase of pH, butthat for disperse red3B was not affected.The nature of the pollutantscould alsoaffect theadsorption effect and rate,which were better and higher for ionic organiccontaminants. While those were slowly and relatively poorfor nonionic organiccontaminants.(4) Three different biochars presented different adsorption characteristics on twoOrganic pollutants (PCP and disperse red3B).Kinetic analysis showed thatthepseudo-second-order kinetics equationcould fit the adsorption data well s, andthe adsorption process was mainly controlled withchemicaladsorptiondominant byfaster reactions.The adsorption behaviors of different biochars for PCP could bewell described by Freundlich adsorption isotherm model, and lower temperaturewas helpful for biochar to adsorb PCP in water. With regard to disperse red3B,the adsorption behaviorcould be better described byTemkin adsorption isothermmodel, thoughit could also be described by Freundlich adsorption isothermmodel.Raising the temperature would be beneficial for adsorption of biocharfordisperse red3B in water.