CN102249450B

CN102249450B - Method for removing trace cadmium from aqueous solution

Info

Publication number: CN102249450B
Application number: CN201110120197A
Authority: CN
Inventors: 孙波; 牛力华; 吴新世; 安钢
Original assignee: Tianjin University of Technology
Current assignee: Tianjin University of Technology
Priority date: 2011-05-11
Filing date: 2011-05-11
Publication date: 2012-08-29
Anticipated expiration: 2031-05-11
Also published as: CN102249450A

Abstract

The invention discloses a method for removing trace cadmium from an aqueous solution. The method comprises the following steps: culturing and analyzing plants growing in a chrome environment, adjusting the pH value of a cadmium-containing aqueous solution with acid or alkali; simultaneously or separately adding ferriferous reagents, carbonates and phosphates or molybdates into the aqueous solution; standing still for depositing, separating out cadmium-slag containing water, wherein the cadmium content of the cadmium-slag containing water is detected to be less than 0.01 mg/L. The method disclosed by the invention is characterized in that through controlling the adding amounts of the ferriferous reagents, the carbonates and the phosphates or the molybdates and the pH value of the cadmium-containing aqueous solution, trace cadmium elements in the cadmium-containing aqueous solution can be removed, and the water treatment time is short, adopted materials are economic and easy to obtain, and no harmful element is added into a system, therefore, the method is an environment-friendly and economic treatment process, and the process can be widely applied to the treatment of cadmium-containing wastewater discharged in the fields of the metal processing industry, the electroplating industry, the leather making industry and the textile industry, and the like.

Description

A kind of method that removes Trace Cadmium in the aqueous solution

The present invention relates to the field of waste water treatment in the environmental technology, particularly a kind of method that removes Trace Cadmium in the aqueous solution.

Along with increasing sharply of trade waste, the water body heavy metal cadmium that is caused is more and more serious.In trade effluent, usually find cadmium, maximum cadmium pollution source is from metal-processing industry, plating industry, curriery and textile industry.Usually contain the poisonous cadmium thing of a great deal of in these industrial effluent.

Traditional method that removes cadmium is suitable for handling the higher waste liquid of cadmium content; Then removal effect is undesirable than the liquid waste disposal at the end but for cadmium content; The agents useful for same consumption is big during processing, produces a large amount of waste residues thus, but also possibly in water body, introduce undesirable ion.

The objective of the invention is to satisfy the needs of economical and efficient simultaneously, and a kind of method that removes microscratch amount cadmium in the aqueous solution is provided in order to protect environment.This method comprises with acid or alkali regulates the pending pH value that contains the cadmium waste liquid, adds and contains ferron, carbonate, phosphoric acid salt or molybdate, and through leaving standstill, post precipitation is isolated and contained cadmium and precipitate.

The invention discloses a kind of method that removes Trace Cadmium in the aqueous solution; It is characterized in that in containing the cadmic pending aqueous solution intersecting or add reagent simultaneously as follows and regulate the pH Value Operations: add and contain ferron; Add carbonate; Add phosphoric acid salt or molybdate, regulate pending pH value of aqueous solution with acid or alkali; Leave standstill solution then, separate out deposition, separate at last and contain the cadmium deposition; Said adjusting pH value is 6-8, and the consumption that contains ferron is that the mol ratio of iron and cadmium is 0.1-10:1, and the consumption of carbonate is that the mol ratio of carbon and cadmium is 0.1-10:1, and the consumption of phosphoric acid salt or molybdate is that the mol ratio of phosphorus or molybdenum and cadmium is 0.1-10:1.

The present invention has developed a kind of method that removes Trace Cadmium in the aqueous solution, can be used for administering trade effluent.This method is taken into account economy and environment protection simultaneously.It can cut the waste, and improves the decreasing ratio of lower concentration cadmium, reduces cost, and reduces environmental pollution simultaneously.

Characteristics of the present invention are through cultivation and analysis to growing plant under the cadmium environment, through control pH value of solution value, and add and contain ferron, carbonate and phosphoric acid salt or molybdate etc., remove the cadmium that contains in the cadmium waste liquid basically fully.The raw materials used economy of the present invention is easy to get, and in system, does not add any harmful element that contains, and the wastewater treatment time is short, and reagent dosage is few, and the waste residue generation is few, and cadmium content can enter secondary network less than 0.01mg/L in the aqueous solution after the processing.Therefore be a kind of environmentally friendly treatment process.The processing that this technology can be widely used in metal-processing industry, electroplate the cadmium wastewater that discharges in fields such as industry, curriery and textile industry.

[embodiment]

The method that removes Trace Cadmium in the aqueous solution of the present invention; Be in containing the cadmic pending aqueous solution, to intersect or add reagent simultaneously as follows and regulate the pH Value Operations: add and contain ferron; Add carbonate; Add phosphoric acid salt or molybdate, regulate pending pH value of aqueous solution with acid or alkali; Leave standstill solution then, separate out deposition, separate at last and contain the cadmium deposition; Said adjusting pH value is 6-8, and the consumption that contains ferron is that the mol ratio of iron and cadmium is 0.1-10:1, and the consumption of carbonate is that the mol ratio of carbon and cadmium is 0.1-10:1, and the consumption of phosphoric acid salt or molybdate is that the mol ratio of phosphorus or molybdenum and cadmium is 0.1-10:1.

The pending aqueous temperature of said method treating processes is 0～80 ℃.The better temperature of said method treating processes is 10～45 ℃.

The said ferron that contains is an iron trichloride, iron protochloride, iron nitrate, tertiary iron phosphate, ferrous sulfate, the mixture of one or more in iron protocarbonate or the iron acetate.

Said carbonate is yellow soda ash, the mixture of one or more in sodium hydrogencarbonate or the salt of wormwood.

Said phosphoric acid salt is sodium phosphate, SODIUM PHOSPHATE, MONOBASIC, Sodium phosphate, dibasic, ammonium phosphate, the mixture of one or more in primary ammonium phosphate or the ammonium hydrogen phosphate.

Said molybdate is a Sodium orthomolybdate, ammonium molybdate, the mixture of one or more in sodium phosphomolybdate or the ammonium phosphomolybdate.

Embodiment 1: measuring cadmium content is the aqueous solution 1L of 36mg/L, adds 50mg nine water iron nitrates and 0.4 g SODIUM PHOSPHATE, MONOBASIC, and the control aqueous temperature is 20 ℃.Under the condition of violent stirring and hierarchy of control pH7-7.2, (regulate with sodium hydroxide or hydrochloric acid when needing), Dropwise 5 0mL contains the aqueous solution of 50 mg sodium hydrogencarbonates.After dropwising, continue to stir 1 hour.Afterwards, be cooled to room temperature, leave standstill, sedimentation also removes by filter and contains the cadmium throw out.The cadmium content of analyzing filtrating through ICP (inductively coupled plasma emmission spectrum, down with) is less than 0.01mg/L, and iron level is less than 0.01mg/L.

Embodiment 2: measuring cadmium content is the aqueous solution 1L of 36mg/L, adds 8mg ferric chloride (FeCl36H2O) and 0.4g ammonium molybdate, uses pH～7 of sodium hydroxide solution regulator solution then, and the control aqueous temperature is 10 ℃.Under the condition of violent stirring and hierarchy of control pH7.2-7.5, drip the aqueous solution that 6mL contains 20 mg yellow soda ash.After dropwising, continue to stir 1 hour.Afterwards, be cooled to room temperature, leave standstill, sedimentation and centrifugal removing contain the cadmium throw out.Less than 0.01mg/L, iron level is less than 0.01mg/L through the cadmium content of icp analysis filtrating.

Embodiment 3: measuring cadmium content is the aqueous solution 1L of 36mg/L, the pH of regulator solution～7.30 ℃ with violent stirring under, add 5mg Sodium Molybdate Dihydrate and 0.4g iron protocarbonate.Control pH value of solution～7 (can add sodium hydroxide or hydrochloric acid regulates) continue to stir 1 hour.Afterwards, leave standstill, sedimentation and centrifugal removing contain the cadmium throw out.Less than 0.01mg/L, iron level is less than 0.01mg/L through the cadmium content of icp analysis filtrating.

Embodiment 4: measuring cadmium content is the aqueous solution 1L of 36mg/L, with its with hcl acidifying to pH～6, under violent stirring; Add 50 mg ferrous sulfate; 30 mg sodium hydrogencarbonates and 5mg sodium phosphate are adjusted to 7.5～8 with pH value of solution then, and the control aqueous temperature is 45 ℃.Continue to stir 2 hours.Afterwards, leave standstill, sedimentation also removes by filter and contains the cadmium throw out.Less than 0.01mg/L, iron level is less than 0.01mg/L through the cadmium content of icp analysis filtrating.

Embodiment 5: measuring cadmium content is the aqueous solution 1L of 36mg/L, under violent stirring, adds the 0.2g tertiary iron phosphate, and 50 mg Potassium orthomolybdates and 30 mg salt of wormwood regulate 7～7.5 with pH value of solution then, and the control aqueous temperature is 10 ℃.Continue to stir 2 hours.Afterwards, leave standstill, sedimentation also removes by filter and contains the cadmium throw out.Through the cadmium content of icp analysis filtrating less than 0.01mg/L.

Claims

1. method that removes Trace Cadmium in the aqueous solution; It is characterized in that in containing the cadmic pending aqueous solution intersecting or add reagent simultaneously as follows and regulate the pH Value Operations: add and contain ferron; Add carbonate; Add phosphoric acid salt or molybdate, regulate pending pH value of aqueous solution with acid or alkali; Leave standstill solution then, separate out deposition, separate at last and contain the cadmium deposition; The said ferron that contains is an iron trichloride, iron protochloride, iron nitrate, tertiary iron phosphate, ferrous sulfate, the mixture of one or more in iron protocarbonate or the iron acetate; Said carbonate is yellow soda ash, the mixture of one or more in sodium hydrogencarbonate or the salt of wormwood; Said phosphoric acid salt is sodium phosphate, SODIUM PHOSPHATE, MONOBASIC, Sodium phosphate, dibasic, ammonium phosphate, the mixture of one or more in primary ammonium phosphate or the ammonium hydrogen phosphate; Said molybdate is a Sodium orthomolybdate, ammonium molybdate, the mixture of one or more in sodium phosphomolybdate or the ammonium phosphomolybdate; Said adjusting pH value is 6-8, and the consumption that contains ferron is that the mol ratio of iron and cadmium is 0.1-10:1, and the consumption of carbonate is that the mol ratio of carbon and cadmium is 0.1-10:1, and the consumption of phosphoric acid salt or molybdate is that the mol ratio of phosphorus or molybdenum and cadmium is 0.1-10:1.

2. according to the described method of claim 1, the pending aqueous temperature that it is characterized in that said method treating processes is 0～80 ℃.

3. according to claim 1 or 2 described methods, the pending aqueous temperature that it is characterized in that said method treating processes is 10～45 ℃.