Modified Hydroxyethyl Cellulose Scale Inhibitor for Reverse Osmosis Membranes

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Solution Overview

Problem

Traditional scale inhibitors are ineffective in preventing silica scale formation in reverse osmosis desalination systems due to poor water solubility and lack of functional groups, and they can cause environmental issues like eutrophication and secondary pollution.

Innovation Solution

A modified hydroxyethyl cellulose scale inhibitor is developed through graft copolymerization with N-(3-dimethylaminopropyl) methyl acrylamide, introducing amino groups to improve affinity and dispersion of silicon dioxide, preventing silica scale formation and being environmentally friendly and biodegradable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional scale inhibitors are used, then alkaline earth metal scale can be inhibited, but they are ineffective against silica scale and cause environmental pollution

Engineering Contradiction:

Improvescale inhibition effectivenessVSAvoidenvironmental pollution

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical structure of cellulose by introducing amino groups through graft copolymerization, changing the functional properties of the polymer to enable effective silica scale inhibition while maintaining environmental friendliness and biodegradability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer structure by grafting N-(3-dimethylaminopropyl) methyl acrylamide onto hydroxyethyl cellulose, combining the water solubility and biodegradability of cellulose with the silica-binding capability of amino groups to achieve both effectiveness and environmental compatibility

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If natural polymers like cellulose are used as scale inhibitors, then environmental friendliness and low cost are achieved, but poor water solubility and lack of functional groups reduce scale inhibition performance

Engineering Contradiction:

Improveenvironmental friendlinessVSAvoidscale inhibition performance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses amino groups as intermediary functional groups that bridge the natural polymer cellulose and the silica scale, enabling the polymer to effectively bind to and inhibit silica scale formation while retaining the environmental benefits of natural polymers

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If silica scale forms on membranes, then water recovery is improved, but transmembrane pressure increases and membrane flux decreases

Engineering Contradiction:

Improvewater recoveryVSAvoidmembrane performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies the scale inhibitor before silica scale can form on the membrane, preventing scale formation in advance through silica polymerization inhibition and colloidal particle dispersion, thereby maintaining membrane performance while achieving water recovery

Inventive Principle:

Principle #10Preliminary action

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 modified hydroxyethyl cellulose scale inhibitor effectively inhibits silica scale formation, maintaining high water solubility and reducing membrane fouling, with a high scale inhibition efficiency of up to 79% and no secondary pollution, suitable for large-scale industrial use.

Implementation Method 1

effectively delay the polymerization of silicon dioxide or disperse silicon dioxide colloidal particles to inhibit the silica scale

Methodology Applied

Scientific EffectPolymerization inhibition:

Implementation Method 2

disperse silicon dioxide colloidal particles to inhibit the silica scale

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 3

the modified hydroxyethyl cellulose scale inhibitor is obtained by graft copolymerization of hydroxyethyl cellulose in nitrogen atmosphere

Methodology Applied

Scientific EffectGraft copolymerization:

Implementation Method 4

Introducing an appropriate amount of cationic groups into natural polymer chains is conducive to improving its affinity and dispersion with silicon dioxide

Methodology Applied

Scientific EffectElectrostatic attraction: Ion Repulsion/Attraction

Data Source

PatentUS11584671B1Modified hydroxyethyl cellulose scale inhibitor for inhibiting silica scale and preparation method thereof

Publication Date: 2023.02.21 NANJING UNIV

AI summary

A preparation method and use of a modified hydroxyethyl cellulose scale inhibitor for inhibiting silica scale are provided. The scale inhibitor is prepared by grafting reaction with hydroxyethyl cellulose as a raw material, ammonium persulfate as an initiator and N-(3-dimethylaminopropyl) methyl acrylamide as a graft monomer. The grafting reaction can introduce grafting chains containing amide group and tertiary amine group into a cellulose molecular chain, so that it can effectively disperse scale forming substances and obtain the efficient environment-friendly scale inhibitor. The scale inhibitor can effectively inhibit the generation of silica scale and prevent the increase of scale particle size, the scale inhibitor is used in a reverse osmosis system, which can effectively alleviate the decline of the membrane flux. The scale inhibitor has a good application prospect in controlling the silica scale on the surface of the reverse osmosis membrane.