Modified Straw Carbon Adsorbent for Phosphate Removal
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Solution Overview
Problem
Current methods for phosphorus removal from lightly polluted water, such as bio-carbon and struvite precipitation, face challenges including short service life, difficult recovery, and pipeline blockage, while modified straw granular carbon struggles with high negative surface charges and poor adsorption efficiency.
Innovation Solution
A combined modified straw activated granular carbon material is developed, loaded with uniform nano-scale metal oxides, created through a process involving pyrolysis, modification with metal salts, and ultrasonic treatment, which enhances compressive strength, adsorption capacity, and phosphorus removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bio-carbon is used for phosphorus removal, then adsorption capacity is improved, but service life is shortened and recovery becomes difficult
Solution Approach 1:
The patent uses composite materials by combining bio-carbon with metal oxides (such as calcium oxide, magnesium oxide, aluminum oxide) to create a composite adsorbent. This composite structure maintains the high adsorption capacity of bio-carbon while the metal oxide components provide structural stability and ease of recovery, thereby extending service life and facilitating regeneration.
2Quantity of substance
If struvite precipitation method is used, then phosphorus and nitrogen removal is improved, but pipeline blockage occurs
Solution Approach 1:
The patent extracts and removes the harmful crystalline struvite formation process by using a different mechanism. Instead of allowing struvite crystals to form and precipitate (which cause blockage), the patent uses adsorption-based removal with composite materials that capture phosphorus without forming blocking crystals, thereby maintaining removal efficiency while eliminating the blockage problem.
Solution Approach 2:
The patent introduces composite adsorbent materials as intermediaries between the phosphorus in wastewater and the removal process. These composite materials (bio-carbon combined with metal oxides) act as mediators that capture phosphorus through adsorption rather than precipitation, avoiding the formation of struvite crystals that would block pipelines.
3Quantity of substance
If granular carbon is modified to improve phosphate removal, then adsorption efficiency is improved, but compressive strength and size are reduced
Solution Approach 1:
The patent applies composite materials by combining bio-carbon with metal oxides to create a composite structure where the metal oxide components provide mechanical strength and structural integrity. This composite approach allows the material to maintain high compressive strength and large particle size while the bio-carbon component provides the high adsorption capacity for phosphate removal.
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 straw activated granular carbon achieves high phosphorus removal rates, extends service life, facilitates recovery, and transforms into a slow-release fertilizer, effectively addressing eutrophication and resource recovery.
Implementation Method 1
bio-carbon prepared by pyrolysis of crop straws under an anoxic or anaerobic condition at a certain temperature
Implementation Method 2
utilizes the strong adsorptive effect of porous adsorbents with large specific surface area on phosphate ions in water bodies
Implementation Method 3
loaded with uniform nano-scale iron/aluminum/magnesium oxides
Data Source
AI summary
A preparation method for a combined modified straw active particulate carbon adsorption material and use of same. The preparation method for the combined modified straw active particulate carbon adsorption material comprises the following steps: 1) mixing straw powders, distilled water, a binder and a composite mineral, then pelletizing same, and then placing same in a tube furnace for pyrolysis to prepare straw particulate carbon; 2) introducing an inert gas into a modification reagent, adjusting the pH value combined and 3) soaking the straw particulate carbon into the combined modification solution for 30 min, and performing cleaning and drying, so as to obtain a combined modified straw active particulate carbon adsorption material. The combined modified straw active particulate carbon has a good adsorption effect on phosphate group in low-pollution water.