| With the rapid development of our country’s economy,people’s demand for water resources is increasing.Water shortages and water pollution have become important factors restricting the sustainable development of social production and affecting people’s normal lives.The pollution of heavy metal ions in the water environment is becoming more and more serious.Among the heavy metal ion pollutants,hexavalent chromium(Cr(VI))comes from the chemical industry,electroplating,mining and metallurgy,tanning and other industries.It has high mobility,strong toxicity and high carcinogenicity.It is the most toxic pollutant in wastewater.One,inorganic phosphorus comes from the chemical,pharmaceutical,chemical fertilizer,textile and other industries,and is the main factor leading to the eutrophication of fresh water bodies.Therefore,the effective removal of hexavalent chromium(Cr(VI))and inorganic phosphorus in wastewater is beneficial to the promotion of industry and agriculture.Sustainable development and safeguarding people’s health are of great significance.At present,the methods for treating hexavalent chromium(Cr(VI))and inorganic phosphorus in wastewater mainly include chemical precipitation,ion exchange,electrolysis,membrane separation,biological,adsorption,etc.Among them,the adsorption method is considered the most operating method.A simple and low-cost method,the development of a kind of adsorption material with good adsorption performance,excellent separation effect and environmentally friendly is the key to the research of adsorption method.In this paper,sodium alginate from a wide range of sources and environmentally friendly was used as the carrier,bagasse biochar with high specific surface area was used as the additive,and ferric chloride solution was used as the cross-linking agent.The three adsorption materials of rubber ball,SA-C-Fe gel ball and SA-C-Fe(C)gel ball were used to remove hexavalent chromium(Cr(VI))and inorganic phosphorus,focusing on the removal of Cr(VI)from wastewater.The performance of and inorganic phosphorus was systematically studied.The removal rate and removal amount of Cr(VI)and phosphorus were used as evaluation indicators to explore the effects of pH,adsorbent dosage,contact time and initial concentration.The change of FTIR,XRD,XPS and other characterizations explored the removal mechanism of Cr(VI)and inorganic phosphorus.First,using bagasse as the raw material and zinc chloride as the activator,the microwave one-step pyrolysis activation experiment was carried out to investigate the effects of microwave power,salt-to-battery ratio and activation time on the specific surface area,pore volume,average pore diameter and For the influence of solid yield,through comparative analysis,the optimal process conditions were determined as follows:microwave activation power 500W,salt-to-battery ratio 2.5:1,microwave activation time 15min;ratio of bagasse biochar prepared under optimal combination conditions The surface area is 1787.642 m2/g,the total pore volume is 1.535 cm3/g,and the average pore diameter is 3.434nm.It has a good pore structure and abundant functional groups.Using sodium alginate with a concentration of 1.5%as the carrier,adding 1 g of biochar prepared under optimal conditions,and 0.1 mol/L ferric chloride as the cross-linking agent,the SA-Fe gel balls and SA-C-Fe were prepared.Gel balls and SA-C-Fe(C)gel balls,SA-Fe and SA-C-Fe balls have irregular folds on the outer surface,and there is a through three-dimensional interlaced fibrous structure inside,which is obtained after carbonization The honeycomb structure of SA-C-Fe(C)gel spheres disappeared,and a large number of regular polygons appeared on the surface of the inner layer,and the main existing form of Fe3+ became magnetic Fe3O4.Using SA-Fe,SA-C-Fe and SA-C-Fe(C)gel balls to carry out static removal experiments on Cr(VI),the removal effect of SA-Fe balls is poor,and the removal rate is greatly affected by pH.With the increase of pH,the removal rate gradually decreases.When pH=2,the removal effect is the best.The whole adsorption process is more in line with the Langmuir isotherm model and the quasi-secondary kinetic model.The Langmuir isotherm model is used to calculate the SA-C-Fe ball and The maximum removal of Cr(Ⅵ)by SA-C-Fe(C)balls was 223.898mg/g and 388.920mg/g,respectively.The removal process is mainly dominated by electrostatic adsorption,ion exchange and redox reactions.Finally,using SA-Fe,SA-C-Fe and SA-C-Fe(C)gels for inorganic phosphorus removal experiments,the adsorption effect is the best at pH=5,and the adsorption process of the three materials is in compliance with the standard The second-level kinetic model shows that chemical adsorption occurs between inorganic phosphorus and the adsorbent.The entire adsorption process of SA-Fe spheres and SA-C-Fe spheres is more consistent with the Langmuir isotherm model.The Langmuir isotherm model is used to calculate the SA-Fe spheres.The maximum adsorption capacity of inorganic phosphorus by SA-C-Fe and SA-C-Fe spheres is 53.794mg/g and 78.758mg/g,respectively.The removal process of SA-C-Fe(C)spheres is more in line with the Freundlich isotherm adsorption model.The adsorption process is mainly composed of The three adsorption mechanisms of volume exchange,electrostatic attraction and surface deposition are dominant. |
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