TWI545080B - A heavy metal scavenger and a method of removing heavy metals from an aqueous solution - Google Patents

Description

Heavy metal collector and method for removing heavy metal in aqueous solution

The present invention relates to a heavy metal collector, and more particularly to a heavy metal collector for removing heavy metals in an aqueous solution, and a method for removing heavy metals in an aqueous solution using the heavy metal collector.

Various industries, such as plastics manufacturing, metal plating, metal finishing and semiconductor manufacturing, generate large amounts of industrial wastewater. These industrial wastewaters usually contain large amounts of heavy metals such as copper, cadmium, lead, mercury, nickel, chromium, manganese, zinc, tin, antimony or arsenic. Because heavy metals are harmful to humans and aquatic organisms, countries around the world have strict regulations on the content of heavy metals in industrial wastewater. With the rise of environmental awareness, the standards for heavy metal content in various countries have become stricter. Therefore, the industry is committed to the development of low-cost and high-efficiency wastewater treatment systems, so that the discharged wastewater meets the increasingly strict heavy metal content specifications.

Another method for removing heavy metals in wastewater is to first add an alkali metal sulfide to the wastewater to form a metal sulfide, and then add a coagulant or a filter aid to destroy the colloidal particles of the solution and accelerate the aggregation of the metal sulfide. And precipitation.

However, since the coagulant or filter aid is composed of an anion a cluster or a polymer containing a cationic group, which accelerates the aggregation or precipitation of metal sulfides, but the large amount of sludge containing metal sulfides must be dehydrated by a solid-liquid separator to make heavy metal sulfides from wastewater. Separation increases the process complexity and processing costs of wastewater treatment.

In view of this, a novel heavy metal collector and utilization The method of removing heavy metals in an aqueous solution by this heavy metal collector is highly desirable in the industry.

It is an object of the present invention to provide a heavy metal collector comprising at least one sulfide and at least one polyamine compound for capturing heavy metals in aqueous solutions, such as copper, cadmium, lead, mercury, nickel, chromium, manganese, zinc, One of or a mixture of heavy metals such as tin, antimony or arsenic.

Another object of the present invention is to provide a method for removing heavy metals in an aqueous solution, the steps comprising: providing an aqueous solution containing a heavy metal; adding at least one sulfide to the aqueous solution; adding at least one polyamine compound to the aqueous solution; The sulfide, the polyamine compound and the heavy metal are allowed to form a precipitate; and the precipitate is separated from the aqueous solution. Among them, according to the above method for removing heavy metals in an aqueous solution according to the present invention, sulfides and polyamine compounds can be added to the aqueous solution containing heavy metals simultaneously or first, without affecting the efficiency of removing heavy metals.

In some embodiments, the above sulfide and the polyamine compound The weight ratio is 0.8:1~40:1, and increasing the addition amount of the polyamine compound can increase the removal rate of heavy metals, so the weight ratio of the preferred sulfide to the polyamine compound is 0.8:1~20:1, The weight ratio of the preferred sulfide to the polyamine compound is from 0.8:1 to 10:1.

In some embodiments, the above sulfides may include, for example, sulfurization One of potassium, potassium hydrosulfide, sodium sulfide, sodium hydrosulfide, sodium polysulfide or a mixture thereof or other sulfides.

In some embodiments, the above polyamine compound includes at least one A diamine compound.

In some embodiments, the above diamine compound, such as 3-di 3-diethyl-amino-propyl-amine (DEAPA), 3-dimethyl-amino-propyl-amine (DMAPA), ethylenediamine, propylenediamine ( 1,3-diaminopropane), N-(2-aminoethyl)ethanolamine or Tetramethylethylenediamine (TMEDA).

Hereinafter, the heavy metal collectors disclosed in the present invention and the conventional techniques for removing copper ions in an aqueous solution will be described with reference to Examples 1 to 7 and Comparative Examples 1 to 6, respectively. The heavy metal collector components of Examples 1 to 7 and Comparative Examples 1 to 6 were prepared in Table 1.

The evaluation methods of the copper removal rates of Examples 1 to 7 and Comparative Examples 1 to 6 were mainly carried out by adding 0.3 ml of the heavy metals of Examples 1 to 7 and Comparative Examples 1 to 6 to 500 ml of an aqueous solution having a copper ion concentration of 42 ppm. The collecting agent was then stirred at a rotation speed of 500 rpm for 30 minutes and then allowed to stand for one hour. Then, the supernatant liquids of Examples 1 to 7 and Comparative Examples 1 to 6 were separately extracted, and the copper content of the supernatant liquid was analyzed by ICP-MASS, and according to the formula (1): Calculate the copper ion removal rate. The evaluation method of the upper liquid haze is mainly to take 10 ml of the upper liquid into a clean 20 ml clear glass bottle, and use pure water as a reference object (haze of 0), and then carry out the sample in haze meter NDH-5000. Analysis, and the haze analysis results were obtained. The analysis results of Examples 1 to 7 and Comparative Examples 1 to 6 are shown in Table 2.

Further, the sodium hydrosulfide and the polyamine compound in Examples 1 to 7 can be added to the aqueous solution containing copper ions simultaneously or first, without affecting the efficiency of removing copper ions.

However, the heavy metal collector of the present invention is not limited to only removing copper ions in an aqueous solution, and other common heavy metals such as cadmium, lead, mercury, nickel, chromium, manganese, zinc, tin, antimony or arsenic may also be utilized. The heavy metal collector disclosed in the present invention is removed.

Further, although the sulfide in the heavy metal collector of each embodiment is exemplified using sodium hydrosulfide, the sulfide in the heavy metal collector disclosed in the present invention includes potassium sulfide, potassium hydrosulfide, sodium sulfide, sulfuric acid. sodium, One of the sodium polysulfides or a mixture thereof or other sulfides, etc., is still within the scope of the present invention.

Further, the polyamine compound in the heavy metal collector of each of the examples Including 3-diethyl-amino-propyl-amine (DEAPA), propylenediamine (1,3-diaminopropane), N-(2-aminoethyl)ethanolamine (N-(2-) Aminoethyl)ethanolamine) or Tetramethylethylenediamine (TMEDA), etc., but the above polyamine compounds are for illustrative purposes only, and are not limited to the above polyamine compounds, and other polyamine compounds such as 3-dimethylamino 3-dimethyl-amino-propyl-amine (DMAPA), ethylenediamine and the like are still within the scope of the present invention.

Formation of each heavy metal trapping agent in Examples 1 to 7 and Comparative Examples 1 to 6 The parts and their weight percentages are summarized in Table 1, and the residual copper ion concentration of the supernatant liquid after the addition of the copper ion aqueous solution in each of the examples and the comparative examples is stirred and then allowed to stand, according to the formula (1) The calculated copper ion removal rate and the haze of the supernatant liquid are summarized in Table 2.

As shown in Table 1, the heavy gold of Examples 1 to 7 and Comparative Examples 1 to 6 The weight percentage of sodium hydrosulfide in the collector is the same, the difference is only in The polyamine compounds shown in Table 1 were added to Examples 1 to 7, and the ratio of the weight percentage of sodium hydrosulfide to the polyamine compound was from 0.8:1 to 40:1; Comparative Example 1 had no added amines. For the compounds, Comparative Examples 2 to 6 were added with a monoamine compound as shown in Table 1.

As shown in Table 2, the copper ion removal rates of Examples 1 to 7 were both large. At 70%, and the copper ion removal rates of Examples 2-7 were higher than 96%; in contrast, in Comparative Examples 1 to 6, the copper ion removal rate was only between 21.4% and 33.3%.

In addition, as shown in Table 2, the metal traps of Examples 1 to 7 were used. The collector removes copper ions in the aqueous solution, and the copper ion removal rate is high, and the haze of the upper liquid layer is lower than 34 Haze%, and the haze of Examples 3 to 7 is lower than 10 Haze%, indicating that the addition example 1~ The heavy metal solution of the 7 heavy metal collector can directly form a precipitate after standing, and does not need to add an organic polymer flocculant, thereby greatly reducing the amount of metal sludge. In contrast, the heavy metal collectors of Comparative Examples 1 to 6 were used to remove copper ions in the aqueous solution, and the copper ion removal rate was low, and the haze of the upper liquid layer was higher than 79 Haze%, indicating that the heavy metals of Comparative Examples 1 to 6 were used. The metal sludge produced by the collector has poor sedimentation efficiency, and it is also necessary to add a flocculant to settle the metal sludge, which not only produces a larger amount of metal sludge, but also increases the cost of removing heavy metals in the aqueous solution.

Although the present invention has been disclosed above in the preferred embodiment, The various embodiments described above may be modified and combined without departing from the spirit and scope of the invention.

Claims (11)

A heavy metal collector comprising at least one sulfide and at least one polyamine compound, and the weight ratio of the sulfide to the polyamine compound is from 0.8:1 to 40:1. The heavy metal collector according to claim 1, wherein the sulfide comprises an inorganic sulfide. The heavy metal collector according to claim 2, wherein the inorganic sulfide comprises potassium sulfide, potassium hydrosulfide, sodium sulfide, sodium hydrosulfide or sodium polysulfide. The heavy metal collector according to claim 1, wherein the heavy metal comprises copper, cadmium, lead, mercury, nickel, chromium, manganese, zinc, tin, antimony or arsenic. The heavy metal collector according to any one of claims 1 to 4, wherein the polyamine compound comprises at least one diamine compound. The heavy metal collector according to claim 5, wherein the diamine compound comprises 3-diethyl-amino-propyl-amine (DEAPA), 3-dimethylaminopropylamine (3) -dimethyl-amino-propyl-amine, DMAPA), ethylenediamine, 1,3-diaminopropane, N-(2-aminoethyl)ethanolamine Or Tetramethylethylenediamine (TMEDA). A method for removing heavy metals in an aqueous solution, the steps of which include: Providing an aqueous solution containing a heavy metal; adding at least one sulfide to the aqueous solution; adding at least one polyamine compound to the aqueous solution, the weight ratio of the sulfide to the polyamine compound is 0.8:1 to 40:1; The sulfide, the polyamine compound and the heavy metal form a precipitate; and the precipitate is separated from the aqueous solution. The method of claim 7, wherein the sulfide comprises an inorganic sulfide. The method of claim 8, wherein the inorganic sulfide comprises potassium sulfide, potassium hydrosulfide, sodium sulfide, sodium hydrosulfide or sodium polysulfide. The method of claim 7, wherein the heavy metal comprises copper, cadmium, lead, mercury, nickel, chromium, manganese, zinc, tin, antimony or arsenic. The method of claim 7, wherein the polyamine compound comprises 3-diethyl-amino-propyl-amine (DEAPA), 3-dimethylaminopropylamine (3-dimethyl-) Amino-propyl-amine, DMAPA), ethylenediamine, 1,3-diaminopropane, N-(2-aminoethyl)ethanolamine or tetramethyl Tetramethylethylenediamine (TMEDA).