In-Situ Layered Double Hydroxide Treatment for Silica and Total Hardness
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Solution Overview
Problem
Existing technologies fail to simultaneously remove silica in various forms and reduce total hardness from natural or waste water without requiring pretreatment steps, leading to inefficiencies and increased operational costs.
Innovation Solution
A process involving the in-situ precipitation of layered double hydroxides, such as hydrotalcite, by adding magnesium hydroxide and a soluble aluminate compound to the water at a pH greater than 8, incorporating scale-forming ions and silica into the lattice of the layered double hydroxide, followed by recycling and regeneration steps for enhanced removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional technologies (microfiltration, ultrafiltration, reverse osmosis, ion exchange, chemical precipitation, flocculation, sand filtration, centrifugation) are used to remove silica and reduce hardness, then removal effectiveness is improved, but process complexity and operational costs increase
Solution Approach 1:
The patent combines multiple treatment functions (silica removal, hardness reduction, and particulate/colloidal material removal) into a single integrated process using layered double hydroxides. Instead of employing sequential separate technologies, the invention uses one material that simultaneously performs all three removal functions, thereby simplifying the overall process while maintaining effective removal of all contaminants
Solution Approach 2:
Layered double hydroxides serve as a universal treatment material that can remove multiple types of contaminants (silica in various forms, scale-forming ions, and particulate/colloidal materials) through a single application. This multi-functional approach eliminates the need for separate treatment steps for each contaminant type, reducing process complexity while achieving comprehensive water purification
2Reliability
If multiple sequential treatment steps are implemented to remove silica and reduce hardness, then removal completeness is improved, but loss of time and increased operational costs occur
Solution Approach 1:
The patent merges multiple sequential treatment operations into a single simultaneous process. Layered double hydroxides are added to water and continuously remove silica, reduce hardness, and eliminate particulate/colloidal materials in one step, eliminating the time delays associated with sequential processing while maintaining complete removal of all contaminants
Solution Approach 2:
The treatment process using layered double hydroxides operates continuously without requiring interruption for step transitions. The material can be added to flowing water and performs removal actions continuously, eliminating idle time between treatment stages and maintaining constant purification effectiveness throughout the process
3Productivity
If high silica concentration water is treated directly, then treatment efficiency is improved, but pretreatment complexity increases
Solution Approach 1:
Layered double hydroxides have inherent capability to treat high silica concentration water directly without requiring prior pretreatment steps. The material's structure and properties enable it to effectively remove silica and other contaminants from water with high silica content, making the treatment system self-sufficient and eliminating complex pretreatment requirements
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
This process effectively removes silica and reduces total hardness without pretreatment, allowing for continuous operation with reduced capital and operational costs, and enhances solute recovery through multiple cycles of layered double hydroxide use.
Implementation Method 1
adding (i) magnesium hydroxide or a precursor of magnesium hydroxide and (ii) a soluble aluminate compound or a precursor of aluminate to said water while maintaining the pH of said stream at pH>8 to produce layered double hydroxide in situ
Implementation Method 2
the layered double hydroxide contains the scale-forming ions in a lattice of the layered double hydroxide and silica is incorporated in the lattice of the layered double hydroxide
Data Source
AI summary
A process for removing silica and reducing total hardness of a natural or waste water containing silica and scale-forming ions comprises adding (i) magnesium hydroxide or a precursor of magnesium hydroxide and (ii) a soluble aluminate compound or a precursor of aluminate to said water while maintaining the pH of said stream at pH>8 to produce a layered double hydroxide in situ, wherein the layered double hydroxide contains the scale-forming ions in a lattice of the layered double hydroxide and silica is incorporated in the lattice of the layered double hydroxide as an interlayer anion and/or bound by the layered double hydroxide via one or more binding modes, wherein the process further comprises a recycling and regeneration step and/or a hydroxide addition step.