The main uses of polyacrylic acid (PAA) in environmental protection include:

1. Wastewater treatment: Polyacrylic acid is widely used in wastewater treatment due to its adsorption, desorption and precipitation properties. It can adsorb heavy metal ions, organic matter and pigments and other pollutants in wastewater, and at the same time form a precipitation in wastewater, separating suspended solids, and playing a role in purifying the water body.

1-Hydroxy Ethylidene-1,1-Diphosphonic Acid (HEDP) is an organophosphate compound widely used in industrial, agricultural and medical applications. Its main advantages and disadvantages are listed below:

When HEDP (Hydroxyethylidene Diphosphonic Acid) is mixed with other chemicals, the following aspects need to be observed to ensure its chemical stability:
I. Dosage control
The dosage of HEDP should be adjusted according to the water quality (e.g., hardness, pH) and the specific application environment to avoid overdose or underdose. Overdosage may lead to side effects such as scaling, corrosion or affecting other chemical reactions. By precisely controlling the dosage, you can ensure that HEDP works optimally in the mixed system while avoiding unnecessary chemical changes.
Second, compatibility check
HEDP should be compatible with other water treatment chemicals (e.g. biocides, disinfectants, flocculants, etc.). Before use, it is recommended to confirm the compatibility of different chemicals through small-scale tests. If there is a compatibility problem, it may affect the effectiveness or even produce adverse reactions. Compatibility check is an important step to ensure the chemical stability of HEDP.
Third, pH control
The effect of HEDP is usually closely related to the pH value of water. When adding HEDP, the pH of the water needs to be monitored and adjusted to ensure its optimal performance. Certain scale inhibitors work best in a specific pH range, so dosing HEDP in the appropriate pH range according to its characteristics helps maintain its chemical stability.
IV. Temperature control
Some scale inhibitors may degrade or fail at high temperatures, although HEDP can remain stable at high temperatures (below 250℃), but in practical applications, the temperature of dosing still needs to be controlled according to the process conditions. Avoid unnecessary chemical changes of HEDP caused by too high temperature.
V. Storage conditions
HEDP should also maintain its chemical stability during storage. Special attention needs to be paid to storage conditions, such as avoiding direct sunlight, high temperature or moisture. HEDP should be placed in a dry, cool place and avoid mixing with other chemicals to minimize the risk of decomposition or deterioration.
VI. Attention to protection and monitoring
Safety protection: HEDP sometimes contains irritating or corrosive components, so it is necessary to wear appropriate protective equipment, such as gloves, glasses, protective clothing, etc. when operating. Avoid contact between HEDP and eyes and skin. Once splashed on the body, flush with plenty of water immediately.
* **Periodic inspection**: Before and after the injection of HEDP should be regularly checked the water quality, especially the water hardness, dissolved oxygen, pH value and other indicators. This helps to detect changes in water quality in time to ensure that HEDP maximizes its effect, and also helps to monitor the chemical stability of HEDP in the mixed system.

HEDP (Hydroxyethylidene Diphosphonic Acid) is a highly efficient organic phosphonic acid scale and corrosion inhibitor with multiple excellent properties. It can form stable complexes with iron, copper, zinc and other metal ions, effectively dissolving the oxides on the metal surface, thus protecting the metal from corrosion. Even under the condition of up to 250℃, HEDP can still play an excellent corrosion and scale inhibition role, and its stability is still excellent in the high pH environment, not easy to hydrolyze, and not easy to decompose under general light and heat conditions.