Lanthanum Hydroxide Adsorption for Phosphorus Removal

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Solution Overview

Problem

Conventional methods for removing phosphorus from sewage, such as physicochemical and biological treatments, are costly and inefficient due to high chemical reagent consumption, sludge production, and low absorption capacity of existing absorbents, which also face challenges in recycling and material costs.

Innovation Solution

A method utilizing lanthanum hydroxide particles as absorbents, with a particle size of 2-20 mm, in conjunction with quartz sands, where phosphorus is absorbed and then desorbed using sodium hydroxide for recycling, achieving high absorption capacity and low-cost phosphorus removal and recycling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional physicochemical treatment methods are used to remove phosphorus, then phosphorus removal effectiveness is improved, but chemical reagent consumption increases and cost increases

Engineering Contradiction:
Improvephosphorus removal effectivenessVSAvoidchemical reagent consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the chemical parameters by using lanthanum hydroxide with specific particle size (2-20 mm) instead of conventional chemical reagents. This parameter change enables phosphorus removal through adsorption rather than chemical precipitation, reducing reagent consumption while maintaining removal effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs lanthanum hydroxide particles as a disposable absorbent that can be easily replaced. These particles have high phosphorus absorption capacity and can be regenerated or disposed of cost-effectively, eliminating the need for expensive chemical reagents and sludge handling.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If conventional biological treatment methods are used to remove phosphorus, then phosphorus removal effectiveness is improved, but sludge production increases and handling difficulty increases

Engineering Contradiction:
Improvephosphorus removal effectivenessVSAvoidsludge production
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces biological treatment processes with a physical-chemical adsorption system using lanthanum hydroxide particles. This substitution eliminates the biological sludge production mechanism while maintaining phosphorus removal effectiveness through direct adsorption onto the absorbent particles.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts phosphorus from sewage directly onto lanthanum hydroxide particles, separating it from the bulk wastewater stream. This extraction approach avoids the sludge formation inherent in biological treatment by directly precipitating phosphorus onto solid absorbent particles rather than through biological decomposition.

Inventive Principle:
Principle #2Taking out (Extraction)

3Quantity of substance

If zeolite particles coated with lanthanum hydroxide are used as absorbent, then phosphorus absorption capacity is improved, but production cost increases and process complexity increases

Engineering Contradiction:
Improvephosphorus absorption capacityVSAvoidproduction cost
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent segments the absorbent system into simple lanthanum hydroxide particles without requiring complex coating processes. This segmentation simplifies manufacturing by using pure lanthanum hydroxide particles directly, eliminating the need for zeolite coating operations while maintaining high phosphorus absorption capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses cost-effective lanthanum hydroxide particles that can be easily produced and replaced. These particles provide high phosphorus absorption capacity at lower production cost compared to coated zeolite particles, as they eliminate the need for expensive coating materials and complex manufacturing processes.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If conventional absorbents are used to remove phosphorus, then phosphorus removal effectiveness is improved, but absorption speed decreases and reaction time increases

Engineering Contradiction:
Improvephosphorus removal effectivenessVSAvoidabsorption speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent optimizes the particle size parameter of lanthanum hydroxide to 2-20 mm, which provides an optimal balance between surface area for absorption and flow characteristics. This parameter optimization enables faster phosphorus absorption rates compared to conventional absorbents, while maintaining high removal effectiveness.

Inventive Principle:
Principle #35Parameter changes

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

The method effectively reduces phosphorus concentration in sewage to less than 0.5 mg/L, recycles lanthanum hydroxide, and produces a high-concentration phosphorus eluate that can be evaporated into fertilizer, demonstrating high absorption capacity and low production costs.

Implementation Method 1

phosphorus in said sewage adheres to the surface of said absorbent

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

adding an solution of sodium hydroxide to said device for reaction of transferring phosphorus adhered to the surface of said absorbent to said solution

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

evaporating said eluate to form fertilizer with phosphorus

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2295380B1Method for removing phosphorus from sewage with Lanthanum hydroxide
Publication Date: 2015.02.25 JIANGXI JDL ENVIRONMENTAL PROTECTION CO LTD
  • EP2295380B1 patent drawingFigure 1~2

AI summary

A method for removing phosphorus includes at least the steps of: 1) placing lanthanum hydroxide (absorbent) into a device for removing phosphorus, and allowing sewage having a phosphorus content of less than 100 mg/L to flow through the device; 2) adding sodium hydroxide (regeneration solution of the absorbent) when the absorption capacity of the device is exhausted, and allowing the regeneration reaction to proceed for between 4 and 12 hours; and 3) collecting eluate from step 2) and recycling phosphorus. The method for removing phosphorus is highly efficient, employs absorbent material having a large absorption capacity and low production cost. The method is simple and convenient to practice, and low in cost.