Activated alumina defluorination regeneration wastewater treatment method

At present, the main methods for removing fluoride from fluorine-containing water include adsorption, electrocoagulation, reverse osmosis, ion exchange, chemical precipitation, and coagulation sedimentation. Among these methods. In the process of fluorine removal by adsorption method, when the adsorbent reaches saturation, it needs to be regenerated to restore its adsorption capacity. At present, the commonly used adsorbent is the activated alumina adsorption method. The following describes the treatment method of activated alumina defluoridation regeneration wastewater: When the activated alumina adsorption reaches saturation, it needs to be regenerated. It can be regenerated with aluminum sulfate or sodium hydroxide. There will be high concentration of fluorine-containing wastewater during the regeneration of activated alumina. The average content is about F-1000mg/L. According to the "Integrated Wastewater Discharge Standard" (GB8978-1996), F- is 10mg/L, so it must be discharged after special treatment reaches the standard. The basic conditions of the activated alumina regeneration wastewater treatment process test: the external dimension of the test device is Φl60mmx3000mm, the internal activated alumina is 30L, and the filling height is 2000mm; the regeneration method uses 1 times 3% NaOH solution to rinse for 2 hours, and then 5 times of clean water to rinse 1.5 h, then neutralize with 1 times 1% H2S04 solution for 1.5 hours, wash with 2 times clear water for 0.5 hours until the effluent pH value is 6-7; the regeneration flow rate is 60L/h. It has been verified by practice that the current good treatment method for activated alumina defluoridation regeneration wastewater is: the three-stage chemical coagulation sedimentation method using CaCl2+PAC+PAM is an effective and applicable process for treating high-content fluorine-containing wastewater, which can stably achieve First level discharge standard of comprehensive sewage discharge standard

19

2020

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06

The relationship between activated alumina carrier and calcination temperature

Activated alumina carrier is widely used in actual industrial production. Among them, activated alumina is an inorganic substance with excellent performance. It can not only be used as dehydration adsorbent, chromatography adsorbent, but also as a carrier, active oxidation The aluminum carrier is widely used in the petrochemical field. It involves various reactions such as reforming, hydrogenation, dehydrogenation, dehydration, etc. What is the relationship between the activated alumina carrier and the roasting temperature? The following is a detailed introduction: The use of hydrothermal treatment and the addition of pore expanders can effectively control the pore structure of the activated alumina carrier, but after forming, the baking process is also one of the important factors affecting the pore structure. Roasting includes processes such as dehydration, dehydroxylation, particle sintering, decomposition or removal of volatile substances, and burning of organic matter. These processes all affect the pore structure of the activated alumina carrier. With the increase of the calcination temperature, the average pore diameter gradually increases. For every 100°C increase in temperature, the proportion of pores larger than 20nm increases by about 5%; the corresponding specific surface area gradually decreases. The increase in the overall pore diameter of activated alumina is mainly caused by the collapse of smaller pores at high temperature to form larger pores. With the increase of the calcination temperature, the content of activated alumina increases, and the specific surface area and pore volume decrease. When the temperature is higher than 450°C, the content remains basically unchanged, while the specific surface area and pore volume still show a downward trend. Activated alumina with high specific surface area and large pore volume can be obtained when the calcination temperature is 450°C. In addition, proper adjustment of the heating rate can completely remove the water in the pores of activated alumina, thereby eliminating agglomeration and fracture.

21

2020

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06

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Activated alumina defluorination regeneration wastewater treatment method

At present, the main methods for removing fluoride from fluorine-containing water include adsorption, electrocoagulation, reverse osmosis, ion exchange, chemical precipitation, and coagulation sedimentation. Among these methods. In the process of fluorine removal by adsorption method, when the adsorbent reaches saturation, it needs to be regenerated to restore its adsorption capacity. At present, the commonly used adsorbent is the activated alumina adsorption method. The following describes the treatment method of activated alumina defluoridation regeneration wastewater: When the activated alumina adsorption reaches saturation, it needs to be regenerated. It can be regenerated with aluminum sulfate or sodium hydroxide. There will be high concentration of fluorine-containing wastewater during the regeneration of activated alumina. The average content is about F-1000mg/L. According to the "Integrated Wastewater Discharge Standard" (GB8978-1996), F- is 10mg/L, so it must be discharged after special treatment reaches the standard. The basic conditions of the activated alumina regeneration wastewater treatment process test: the external dimension of the test device is Φl60mmx3000mm, the internal activated alumina is 30L, and the filling height is 2000mm; the regeneration method uses 1 times 3% NaOH solution to rinse for 2 hours, and then 5 times of clean water to rinse 1.5 h, then neutralize with 1 times 1% H2S04 solution for 1.5 hours, wash with 2 times clear water for 0.5 hours until the effluent pH value is 6-7; the regeneration flow rate is 60L/h. It has been verified by practice that the current good treatment method for activated alumina defluoridation regeneration wastewater is: the three-stage chemical coagulation sedimentation method using CaCl2+PAC+PAM is an effective and applicable process for treating high-content fluorine-containing wastewater, which can stably achieve First level discharge standard of comprehensive sewage discharge standard

19

2020

/

06

The relationship between activated alumina carrier and calcination temperature

Activated alumina carrier is widely used in actual industrial production. Among them, activated alumina is an inorganic substance with excellent performance. It can not only be used as dehydration adsorbent, chromatography adsorbent, but also as a carrier, active oxidation The aluminum carrier is widely used in the petrochemical field. It involves various reactions such as reforming, hydrogenation, dehydrogenation, dehydration, etc. What is the relationship between the activated alumina carrier and the roasting temperature? The following is a detailed introduction: The use of hydrothermal treatment and the addition of pore expanders can effectively control the pore structure of the activated alumina carrier, but after forming, the baking process is also one of the important factors affecting the pore structure. Roasting includes processes such as dehydration, dehydroxylation, particle sintering, decomposition or removal of volatile substances, and burning of organic matter. These processes all affect the pore structure of the activated alumina carrier. With the increase of the calcination temperature, the average pore diameter gradually increases. For every 100°C increase in temperature, the proportion of pores larger than 20nm increases by about 5%; the corresponding specific surface area gradually decreases. The increase in the overall pore diameter of activated alumina is mainly caused by the collapse of smaller pores at high temperature to form larger pores. With the increase of the calcination temperature, the content of activated alumina increases, and the specific surface area and pore volume decrease. When the temperature is higher than 450°C, the content remains basically unchanged, while the specific surface area and pore volume still show a downward trend. Activated alumina with high specific surface area and large pore volume can be obtained when the calcination temperature is 450°C. In addition, proper adjustment of the heating rate can completely remove the water in the pores of activated alumina, thereby eliminating agglomeration and fracture.

21

2020

/

06

< 12 >