Water Treatment Activated Carbon
Summary
Products are currently used for water
treatment have activated carbon, silicon oxide, activated alumina, zeolite,
diatomite and ion-exchange resins. The aluminum - silicone sorbents are
hydrophilic adsorbent, they are selective adsorption to polar substances, so
generally as the moisture absorption agent, dehydrant and nonpolar solution
adsorbent. Activated carbon is a hydrophobic adsorbent, has strong adsorption
to the organic compounds in aqueous solution, so generally as the city sewage
and industrial wastewater treatment adsorbents.
The raw materials of water treatment
activated carbon have coconut shells, walnut shell, apricot, peach shell, wood,
coal and so on, the coconut shell activated carbon is considered the best water
treatment activated carbon. Water treatment activated carbon has powder,
granule and columnar, among them granule is the most widely used. The smaller
granularity, the faster absorption, but head loss increases, usually in 8-30
mesh is better.
Water treatment activated carbon three
requirements: large adsorption capacity, quick adsorption rate, good mechanical
strength. In addition, Yuanying activated carbon has large specific
surface area, abundant pore structure, not easy off powder, low base layer resistance,
chemical stability, high degree of purification, long service life, easy
regeneration.
The
main influencing factors to water treatment process of activated carbon
Due to the adsorption process and action
principle of activated carbon water treatment involves more complex, so there
are a lot of influence factors. The main factors include the properties of
activated carbon, pollutants properties in water, solution PH, solution
temperature, carbon treatment process principle, selective operating parameters
and operating conditions.
Activated carbon adsorption capacity is
mainly related to its specific surface area, the greater specific surface area
is, the better adsorption property is. Adsorption rate is mainly related to
grain size and pores distribution of activated carbon. Water treatment
activated carbon requires abundant transition hole (radius is 20 to 1000
angstroms), that is conducive to the adsorbate (pollutants in water) spreads to
the hole. In addition, activated carbon surface chemical properties, polarity
and electric charge also affect the adsorption effect.
Application
Activated carbon surface has a large number
of functional groups such as hydroxyl and carboxyl, can undertake chemical
adsorption and electrostatic attraction to various organic substances.
Activated carbon can remove the organic substances such as humic acid, fulvie
acid, lignosulfonic acid etc. which are harmful to anion exchange agent; also
can remove the substances such as free chlorine residual which is harmful to
cation exchanger. Generally, activated carbon can remove 63%-68% colloidal
substances, around 50% ferrum, 47%-60% organic substances. Activated carbon has
strong adsorption capacity to water dissolved organic contaminants, such as
benzenes, phenols, petroleum and petroleum products. Organic pollutants by
biological method and chemical method is difficult to remove, such as
chrominance, foreign odor, methylene blue surface active substances,
herbicides, pesticides, agricultural chemicals, synthetic detergents, synthetic
dyes, amine compounds, and many synthetic organic compounds, activated carbon
have good effect to removal them. Activated carbon has strong adsorption
capacity to some heavy metal compounds, such as mercury, plumbum, ferrum,
nickel, chromium, zinc, cobalt, etc., therefore, activated carbon has a good
effect to electroplating wastewater and treatment smelting wastewater
treatment. Activated carbon is widely used for domestic water and food
industry, chemical industry, electric power industry, etc. for water
purification, dechlorination, oil removal and deodorization.
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