CN103754867A

CN103754867A - Method for preparing active carbon by utilizing high-COD organic wastewater in alkali deweighing technology of dyeing plant

Info

Publication number: CN103754867A
Application number: CN201310643874.4A
Authority: CN
Inventors: 郑乐平; 陆永生; 马国文; 吴祖龙; 王展; 张在屋
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2013-12-05
Filing date: 2013-12-05
Publication date: 2014-04-30

Abstract

The invention relates to a method for preparing active carbon by utilizing high-COD organic wastewater in an alkali deweighing technology of a dyeing plant, and belongs to the technical field of environment engineering wastewater treatment. The method is mainly characterized in that powdery active carbon is prepared by using filter residues generated after the physicochemical treatment of the high-COD organic wastewater. The method comprises the following steps: adjusting the pH value of wastewater to an appropriate value, and adding a soluble calcium salt, a coagulant and a coagulant aid to make difficult-biochemical-treatment organic pollutants react and be converted to form alkaline-earth metal salt; and carrying out solid-liquid separation to obtain the filter residues, and heating the filter residues under the protection of nitrogen in an activation furnace at 550-700DEG C for carbonization to obtain the active carbon. The obtained active carbon has a good adsorption effect on a plurality of common dyes, and can be directly used for the wastewater adsorption treatment. The method has the advantages of low energy consumption and no exhaust gas emission, and allows outlet water to be directly mixed with other low-concentration-COD wastewater and the obtained mixture to undergo biochemical treatment. The product active carbon can be directly used for the wastewater treatment to realize the treatment of wastes with processes of wastes against one another.

Description

Utilize high COD organic waste water in printing and dyeing mill's caustic reduction processing to prepare the method for gac

Technical field

The present invention relates to a kind of high COD organic waste water in " caustic reduction processing " and prepare the method for gac, belong to environmental engineering technical field of waste water processing.

Background technology

High COD organic waste water results from the production process of the products such as alcohol, synthon, microbiotic, COD is up to tens thousand of mg/L, tradition anaerobic biological method or coagulation sedimentation method are poor to the treatment effect of such waste water, the residue producing conventionally adopts sanitary landfill, burning or directly throws extra large mode and process, so not only cause organism wastes a large amount of in such waste water, also can cause serious secondary pollution to soil, water body.

Patent CN200910117355.8, CN200610128370.9, CN200910012982.5 are respectively from biochemical, materialization multistage treatment method, coagulating sedimentation intensive filtration method, alkali-earth metal modified formation Pickering emulsion process is studied the processing of such waste water, but all has the shortcoming that the treatment time is long, processing residue is mishandling, prospects for commercial application is poor.

The present invention proposes a kind of combination physics-chemically pretreating process on traditional physical chemistry method basis, guaranteeing that water outlet is easy under the prerequisite of biochemical treatment, the pollutent of the high COD organic waste water in " caustic reduction processing " is separated from waste water with alkaline-earth metal salt form, in order to prepare gac, solve residue handling problems.The method consuming time short, energy consumption is low, follow-up biochemical intractability is low, overall process cost is little.

Summary of the invention

The present invention is high in order to overcome " caustic reduction processing " high COD treatment of Organic Wastewater cost, and complicated operation is not easy to the shortcoming of biochemical treatment, provides a kind of less energy-consumption, cost " alkali decrement " wastewater treatment residue as resources little, non-secondary pollution to utilize method.The present invention is a kind of method of utilizing high COD organic waste water in printing and dyeing mill's caustic reduction processing to prepare gac, it is characterized in that having following process and step:

A. to the organic waste water of taking from certain printing and dyeing mill's caustic reduction processing, under heating condition, do not adding salt acid for adjusting pH to 9 ~ 10; By 12 ~ 18g/L, add any in calcium chloride, nitrocalcite soluble calcium salt at ambient temperature, rapid stirring 2min forms organic alkaline earth salt;

B. continue to add Al ₂(SO ₄) ₃, AlCl ₃, polymerize aluminum chloride (PAC) any aluminum salt and non-wherein

Polyacrylamide (NPAM); Its dosage is respectively 0.5 ~ 1g/L, 25 ~ 40mg/L; After low rate mixing 20min, move into settling bowl, standing postprecipitation is separated with supernatant liquor; The aluminium salt that this waste water is used is better and have certain decolorizing effect compared with the coagulation effect of other coagulating agent; The NPAM using can the better sedimentation that must accelerate suspended particles compared with the coagulant aids of other types; Water outlet now can directly mix and carry out biochemical treatment again with the waste water of other technological processs generations; Its COD clearance is up to 78%; Gained filter residue is after filtration dried and both must be prepared the raw material of gac;

C. the filter residue after drying is placed in to activation furnace, under nitrogen protection condition, is warming up to 550 ~ 700 ^oc, temperature rise rate is 10 ~ 15 ^oc/min, carbonization time approximately 1 ~ 3 hour is cooled to room temperature and obtains its lytic activity charcoal under nitrogen protection.This property charcoal all has good adsorption effect to multiple common dyestuff, can be directly used in the processing of other processing wastewaters of printing and dyeing mill.

The features and advantages of the invention are:

(1) main processes of " alkali decrement " is in high temperature alkaline solution, terylene artificial silk to be soaked, make the terephthalic acid on fiber, a small amount of ethylene glycol partly peel off and reach decrement object, thereby the principal pollutant in waste water are terephthalic acids, by present method to this material effective and reasonable dispose.

(2) present method can be processed " alkali decrement " organic waste water that COD concentration is 5000-50000mg/L, in conjunction with chemical reaction and coagulating agent combination treatment, can be low in energy consumption, make the total clearance of COD reach higher level basic non-secondary pollution in the situation that, make the water outlet can be easily by biochemical treatment.

(3) calcium salt residue preprocessing process being produced obtains powdered active carbon by activation, not only solved the processing problem of terephthalate waste residue, the gac being prepared into all has good adsorption effect to common multiple dyestuff, and its methylene blue adsorption value is 15ml/0.1g.This gac can be directly used in other techniques of printing and dyeing mill and produce in the treating processes of waste water, reaches the good result of the treatment of wastes with processes of wastes against one another.

(4) CaCl in preprocessing process ₂dosage is within the scope of 12-18g/L, and the clearance of water outlet COD is substantially constant, however the follow-up transformation efficiency of preparing gac within the scope of 30-50%, change, calcium salt is more, transformation efficiency is higher.Thereby can, according to substantial activity charcoal needs, cost control, select suitable calcium salt dosage.

(5) the inventive method easy control of reaction conditions, reaction time consumption is short, energy consumption is low, can process " alkali decrement " organic waste water of high COD, and the value that reclaims the prepared gac of residue can significantly reduce processing cost.

Accompanying drawing explanation

Figure of description 1 is the schema that the high COD organic waste water in utilization of the present invention " caustic reduction processing " is prepared gac.

Embodiment

After now embodiments of the invention being specifically described in.

Embodiment:

Referring to Fig. 1, in equalizing tank, add and take from the Zhejiang printing and dyeing enterprise waste water in " caustic reduction processing " stage, its COD is about 30000 mg/L, with 20% technical hydrochloric acid, regulate wastewater pH to 10, proceed to agitated pool, and press the congenial enough calcium chloride of 16g/L waste water and react with organic pollutant, after rapid stirring 2min, by 1g/L waste water, add Al ₂(SO ₄) ₃after continuing to stir 5min, by 25mg/L, add NPAM, after low rate mixing 20min, move into settling bowl, standing about 20min postprecipitation is substantially separated with supernatant liquor, now supernatant C OD is reduced to approximately 6000 mg/L, COD clearance is 78%, and this water outlet can be introduced biochemical treatment tank and directly mix and carry out biochemical treatment again with other processing wastewaters.

After being filtered, dried, gained throw out puts into activation furnace, under nitrogen protection, by 15 ^oc/min is warming up to 600 ^oc, continues to pass into nitrogen after activation 3h and obtains finished product powdered active carbon to being cooled to room temperature.After measured, the generation of organic bases earth metal salt residue is about 14kg/ ton waste water, the transformation efficiency of being prepared gac by residue is about 40%, the methylene blue adsorption value of this gac is 15mL/0.1g, its to Viola crystallina, rhodamine B, tropeolin-D, orange N, Congo redly all have a good adsorption effect, can directly use it in wastewater treatment process, if by the calculation of price of approximately 4000 yuan/ton of commercial powder shaped activated carbons, the income of preparing gac generation is about 22 yuan/ton of waste water.

Claims

1. utilize high COD organic waste water in printing and dyeing mill's caustic reduction processing to prepare a method for gac, it is characterized in that thering is following technological process and step:

A. to the high COD organic waste water of taking from certain printing and dyeing mill's caustic reduction processing, under heating condition, do not adding salt acid for adjusting pH to 9 ~ 10.By 12 ~ 18g/L, add any in calcium chloride, nitrocalcite soluble calcium salt at ambient temperature, rapid stirring 2min forms organic alkaline earth salt;

B. continue to add Al ₂(SO ₄) ₃, AlCl ₃, polymerize aluminum chloride (PAC) wherein any aluminum salt and non-ionic polyacrylamide (NPAM); Its dosage is respectively 0.5 ~ 1g/L, 25 ~ 40mg/L; After low rate mixing 20min, move into settling bowl, standing postprecipitation is separated with supernatant liquor; The aluminium salt that this waste water is used is better and have certain decolorizing effect compared with the coagulation effect of other coagulating agent; The NPAM using can the better sedimentation that must accelerate suspended particles compared with the coagulant aids of other types; The waste water that water outlet now can directly produce with other technological processs mixes regeneration to be processed; Its COD clearance is up to 78%; The raw material of preparing gac is dried and obtained to gained filter residue after filtration;