CN106219685A

CN106219685A - The different chelating agent assisted electrochemical of a kind of utilization removes Cr in water3+method

Info

Publication number: CN106219685A
Application number: CN201610810307.7A
Authority: CN
Inventors: 刘耀兴; 陈佳辉; 陈日耀
Original assignee: Fujian Normal University
Current assignee: Fujian Normal University
Priority date: 2016-09-08
Filing date: 2016-09-08
Publication date: 2016-12-14
Anticipated expiration: 2036-09-08
Also published as: CN106219685B

Abstract

The present invention relates to the different chelating agent assisted electrochemical of a kind of utilization and remove Cr in water³⁺Method.Cr will be contained³⁺Waste water introduces in reative cell, add a certain amount of chelating agent and supporting electrolyte sodium sulfate, using SWCN modify rustless steel mesh sheet as negative electrode, titanium net is anode, regulation reative cell pH is certain value, with certain electric current density, after energising processes certain time, with spectrophotometer measurement and calculate Cr³⁺Clearance, obtaining can the waste water of qualified discharge.The present invention has: 1, adds dissimilar chelating agent and can change Cr³⁺Form in aqueous so that it is be easily removed.2, Cr is being improved³⁺Energy consumption of reaction is reduced while clearance.

Description

The different chelating agent assisted electrochemical of a kind of utilization removes Cr in water3+Method

Technical field

This patent relates to a kind of technical field of waste water processing, is specifically related to the different chelating agent assisted electrochemical of a kind of utilization and goes Except trivalent chromium (Cr in waste water³⁺) method.

Background technology

Chromium is widely used in plating, intermetallic composite coating, pigment, leather processing, chemical drugs manufacture, electronic equipment and catalysis The industries such as industry, in all conglomeraties, there is a large amount of Cr every day⁶⁺And Cr³⁺Acid waste water produces.Along with people are to Cr⁶⁺Toxicity recognize Know, Cr⁶⁺Use obtained strict control, and Cr in chromate waste water³⁺Still a large amount of existence and proportion become in increasing Gesture.Although Cr³⁺Toxicity not as Cr⁶⁺Strongly, but in natural environment, there is Cr⁶⁺And Cr³⁺Mutual conversion phenomena, Cr³⁺Right The mankind and natural environment have great potential threat, it is therefore necessary to substantial amounts of Cr³⁺Waste water processes.

At present, Cr in aqueous solution³⁺Removing method mainly include absorption, electricity flocculation, membrance separation, hydroxide precipitation method Deng, but all there are some unavoidable shortcomings.It is slow to there is absorption pollutant speed in absorption method, and adsorption capacity is less and Yi Shouhuan The problems such as border factor impact；It is big to there is power consumption in electricity flocculation, and energy consumption is high, the problems such as delivery turbidity is bigger；Membrane separation process is processing During low concentration wastewater, easily occurring concentration polarization to cause film fouling, energy consumption raises, and effluent quality declines.In various processing methods In, hydroxide precipitation method is most common method, but hydroxide precipitation method can produce a large amount of mud, need to carry out at secondary Reason, meanwhile, according to the research of Erdem et al., chromium element easily dissolution from precipitating sludge in hydroxide precipitating sludge, form two Secondary pollution.Thus, it is necessary to research and develop that a kind of energy consumption is low, non-secondary pollution and the Cr of metal recovery can be carried out³⁺Waste water process side Method.

Electrochemical process is the another kind of water technology grown up over nearly 60 years, has low, the non-secondary pollution of energy consumption etc. Feature, has the biggest potentiality in terms of processing heavy metal wastewater thereby.CNT is a kind of new carbon found in 1991, There is high-specific surface area, satisfactory electrical conductivity and high mechanical properties, in adsorption treatment water pollution, shown wide application Prospect.Rustless steel is a kind of common conductive metal material, and resistance to acids and bases, mechanical strength, electric conductivity are the most excellent.

Cr³⁺Mainly with ［ Cr (H in the pH solution less than 4₂O)₆?³⁺Form exist, its be one with Cr³⁺Centered by, H₂O Highly stable regular octahedron structure for summit.And Cr³⁺And H₂Average bond length between O is 1.99, and this makes Cr³⁺It is difficult to Acquisition electronics is reduced.As can be seen here, Cr to be made³⁺It is easily obtained electronics to be reduced, need to first change its stable morphosis, Increase Cr³⁺-H₂Bond length between O.The good news is, when water body exists energy and the Cr such as formic acid, ammonium formate, acetic acid and oxalic acid³⁺Send out When giving birth to the material of strong complexing, ［ Cr (H₂O)₆?³⁺Stable positive octahedral structure can be broken, and this is conducive to Cr³⁺Further Obtain electronics and be reduced to Cr atom, thus be removed.

The deposition SWCN rustless steel mesh sheet that this patent uses electrophoretic deposition to prepare is electrode, with different complexations Agent assists this Electrode treatment containing Cr³⁺Waste water, improves Cr in waste water whereby³⁺Removal effect.

Summary of the invention

The purpose of this patent is to use dissimilar chelating agent to remove Cr³⁺, to realize discharged wastewater met the national standard.

Cr will be contained³⁺Waste water introduces in reative cell, adds chelating agent and sodium sulfate, the stainless (steel) wire modified with SWCN Sheet is as negative electrode, and titanium net is anode, regulates reative cell pH value, and energising processed after certain time, with spectrophotometer measurement and count Calculate Cr³⁺Clearance, obtaining can the waste water of qualified discharge.

Described chelating agent is the one in formic acid, oxalic acid, acetic acid, citric acid.

Described chelating agent addition is Cr³⁺Between the 5% ~ 20% of mass fraction.

Described pH value controls between 2 ~ 5.

Described energising processes, and its electric current density controls at 0.5 ~ 3mA/cm²Between.

Described sodium sulfate, its mass fraction is 3 ~ 15g/L.

Described energising processes, and the process time is 200 ~ 250min.

Described reative cell is traditional single chamber three-electrode electro Chemical system.In this electro-chemical systems, SWCN The rustless steel mesh sheet modified is negative electrode, and titanium net is anode, and reference electrode is saturated calomel electrode.Experiment uses spectrophotometric after terminating Measurement amount also calculates Cr³⁺Clearance.

There is advantages that

1, add dissimilar chelating agent and can change Cr³⁺Form in aqueous so that it is be easily removed.

2, Cr is being improved³⁺Energy consumption of reaction is reduced while clearance.

Accompanying drawing explanation

Fig. 1 is to add different chelating agent Cr³⁺Clearance changes over curve.

Detailed description of the invention

Embodiment 1

Formic acid auxiliary SWCN stainless (steel) wire plate electrode removes Cr³⁺Waste water:

By 200mL containing Cr³⁺Waste water is (containing Cr³⁺: 6.13mg/L) introduce in reative cell, add 2g sodium sulfate, with single The stainless (steel) wire plate electrode that pipe is modified is as negative electrode, and titanium net is anode, and controlling reative cell pH is 4.0, and keeping electric current density is 2 mA/cm², formic acid addition is 0.2452mg.The process time is 210min.Containing Cr³⁺Waste water after treatment, measures with spectrophotometric Measure and calculate Cr³⁺Clearance, shows Cr³⁺Concentration reduces to 1.43mg/L, and clearance is 76.7%.

The present embodiment use containing Cr³⁺Waste water is simulated wastewater.

Embodiment 2

Acetic acid auxiliary SWCN stainless (steel) wire plate electrode removes Cr³⁺Waste water:

By 200mL containing Cr³⁺Waste water is (containing Cr³⁺: 6.35mg/L) introduce in reative cell, add 1.6g sodium sulfate, with single The stainless (steel) wire plate electrode that pipe is modified is as negative electrode, and titanium net is anode, and controlling reative cell pH is 3.5, and keeping electric current density is 2.2 mA/cm².Acetic acid addition is 0.2540mg.Chemical process time is 240min.Containing Cr³⁺Waste water after treatment, uses spectrophotometric Measurement amount also calculates Cr³⁺Clearance, shows Cr³⁺Concentration reduces to 0.96mg/L, and clearance is 84.9%.

Embodiment 3

Oxalic acid auxiliary SWCN stainless (steel) wire plate electrode removes Cr³⁺Waste water:

By 200mL containing Cr³⁺Waste water is (containing Cr³⁺: 6.49mg/L) introduce in reative cell, add 2g sodium sulfate, with SWCN The stainless (steel) wire plate electrode modified is as negative electrode, and titanium net is anode, and controlling reative cell pH is 2.5, and keeping electric current density is 2.5 mA/cm².Oxalic acid addition is 0.2596mg.Chemical process time is 240min.Containing Cr³⁺Waste water after treatment, uses spectrophotometric Measurement amount also calculates Cr³⁺Clearance, shows Cr³⁺Concentration reduces to 0.51mg/L, and clearance is 92.1%.

Embodiment 4

Citric acid auxiliary SWCN stainless (steel) wire plate electrode removes Cr³⁺Waste water:

By 200mL containing Cr³⁺Waste water is (containing Cr³⁺: 6.30mg/L) introduce in reative cell, add 1.6g sodium sulfate, with single The stainless (steel) wire plate electrode that pipe is modified is as negative electrode, and titanium net is anode, and controlling reative cell pH is 3.0, and keeping electric current density is 2.5 mA/cm².Citric acid addition is 0.2520mg.Chemical process time is 250min.Containing Cr³⁺Waste water after treatment, uses light splitting light Degree measurement amount also calculates Cr³⁺Clearance, shows Cr³⁺Concentration reduces to 0.21mg/L, and clearance is 96.7%.

Claims

1. one kind utilizes different chelating agent assisted electrochemical to remove Cr in water³⁺Method, concrete grammar is as follows:

Cr will be contained³⁺Waste water introduces in reative cell, adds chelating agent and sodium sulfate, regulates reative cell pH value, and energising processes a timing After between, with spectrophotometer measurement and calculate Cr³⁺Clearance, obtaining can the waste water of qualified discharge.

The different chelating agent assisted electrochemical of a kind of utilization the most according to claim 1 removes Cr in water³⁺Method, its feature It is that described chelating agent is the one in formic acid, oxalic acid, acetic acid, citric acid；Described chelating agent addition is Cr³⁺Quality is divided Between the 5% ~ 20% of number.

The different chelating agent assisted electrochemical of a kind of utilization the most according to claim 1 removes Cr in water³⁺Method, its feature It is described pH value, controls between 2 ~ 5.

The different chelating agent assisted electrochemical of a kind of utilization the most according to claim 1 removes Cr in water³⁺Method, its feature Being that described energising processes, its electric current density controls at 0.5 ~ 3mA/cm²Between.

The different chelating agent assisted electrochemical of a kind of utilization the most according to claim 1 removes Cr in water³⁺Method, its feature Being described sodium sulfate, its mass fraction is 3 ~ 15g/L.

The different chelating agent assisted electrochemical of a kind of utilization the most according to claim 1 removes Cr in water³⁺Method, its feature Being that described energising processes, the process time is 200 ~ 250min.

The different chelating agent assisted electrochemical of a kind of utilization the most according to claim 1 removes Cr in water³⁺Method, its feature Be described reative cell, with SWCN modify rustless steel mesh sheet as negative electrode, titanium net is anode, and reference electrode is full And calomel electrode.