Selenium Treatment in Coal Gasification Wastewater
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Solution Overview
Problem
Selenium-treating performance decreases over time due to the elution of noble metal ions from catalysts during catalytic wet oxidation treatment in selenium-containing water, which are not effectively addressed by existing methods.
Innovation Solution
A method and apparatus that involve pretreating selenium-containing water with a mixture of metallic titanium and a simple metal baser than titanium to remove noble metal ions, which are then reduced and precipitated, preventing their deposition on titanium surfaces and maintaining reduction reaction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If selenium-containing water is subjected to reduction treatment by contacting with a mixture of metallic titanium and a simple metal baser than titanium, then selenium is removed by reduction reaction, but noble metal ions eluted from catalysts deposit on titanium surfaces and narrow the surface regions contributing to reduction reaction, resulting in decrease of selenium-treating performance with time
Solution Approach 1:
The invention applies preliminary action by introducing a pretreatment step before the main reduction treatment. In this pretreatment, metallic zinc is contacted with the selenium-containing water to remove noble metal ions through displacement reaction before the water enters the reduction treatment stage, preventing the noble metal ions from depositing on titanium surfaces and maintaining stable treatment performance over time.
Solution Approach 2:
The invention uses metallic zinc as an intermediary substance that mediates between the noble metal ions and the titanium reduction catalyst. The zinc selectively removes noble metal ions through displacement reaction, acting as a protective intermediary that prevents harmful deposits on the titanium surface while allowing the reduction treatment to proceed effectively.
2Adaptability or versatility
If noble metal catalyst is used for catalytic wet oxidation treatment of COD components and ammonia, then comprehensive treatment is achieved, but noble metal ions are eluted from the catalyst to act as inhibitory agents in subsequent selenium reduction treatment
Solution Approach 1:
The invention applies the taking out principle by extracting and removing noble metal ions from the selenium-containing water through a dedicated pretreatment step using metallic zinc. This separation removes the harmful inhibitory substances before they can affect the selenium reduction treatment, while preserving the beneficial comprehensive treatment capabilities of the noble metal catalyst in the oxidation stage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Stably and efficiently treats selenium-containing water by removing noble metal ions prior to reduction treatment, preventing a decrease in selenium-treating performance over time and ensuring consistent treatment efficiency.
Implementation Method 1
selenium in the selenium-containing water is reduced
Implementation Method 2
ions of the noble metal in the selenium-containing water are reduced on the surfaces of metallic titanium particles
Implementation Method 3
to form precipitates, which adhere to the surfaces of the metallic titanium particles
Implementation Method 4
the surfaces of the metallic titanium particles are plated with the noble metal
Implementation Method 5
a portion of the baser simple metal is eluted
Data Source
AI summary
A method and an apparatus for treating coal gasification wastewater containing selenium and ions of a metal nobler than titanium eluted from a noble metal catalyst in a catalytic wet oxidation treatment using the noble metal catalyst, the method includes a pretreatment process removing the ions of the metal nobler than titanium and a selenium reduction process contacting the coal gasification wastewater with a mixture of metallic titanium and a simple metal baser than metallic titanium whereby a portion of the simple metal baser than metallic titanium is eluted, and the selenium in the coal gasification wastewater becomes reduced.