Factors influencing the biochemical
degradation of LAS
Physical and Chemical Properties
Appearance under normal temperature as
milky, liquid material; when it is warmed, it becomes transparent liquid.
Soluble in water while insoluble in chloroform. Air bubbles would be generated
when in water, which is of such functions as dispersing, decontamination and
reducing surface tension, etc. It is easy to form stratified layer after long
storage time while the chemical properties do not change, so it is better to
use after thorough stirring.
The temperature
Microbial growth need to be in the right
temperature, only in the appropriate temperature, the degradation rate of LAS
was biggest. Optimum growth and microorganism decomposition temperature at
30 ℃, and its
activity in a certain temperature range varies with temperature
Increased. Studies have shown that at 20 ℃, linear alkyl benzene sulfonate
(LAS) degradation in the aquatic system speed is (1.5 ~ 3.5 ℃) 20 times. Chemical reaction rate
is affected by temperature. So the temperature can affect LAS biochemical
degradation.
PH
In general, the pH of water, microbial
activity has a direct impact. Suitable pH range of different microorganisms.
Degradation of LAS microorganisms such as bacteria, actinomyces, pH change will
cause the change of cell charge, at the same time will affect the activity of
enzyme in cells. However, for a river, the influence of pH value on the LAS is
not very obvious.
The initial concentration of LAS
Pollutant itself to microbes, generally
speaking, there are certain toxicity, and the toxicity increased with the
increase of pollutants concentration increased. Studies show that when the
concentration of LAS > 10 mg/L, the inhibition of its degradation is
obvious. And studies have shown that LAS can affect aerobic degradation of
organic matter in PH self-adjusting ability. When the initial concentration of
LAS is greater than 20, then stop the aerobic degradation of organic matter in
the PH of self-adjusting ability, reduce microbial activity.
Effect of dissolved oxygen
Most of the LAS aerobic degradation is mainly to increase the dissolved oxygen concentration , can significantly increase the degradation of LAS . Aerobic biodegradation of LAS mainly contains three kinds of mechanism: ( 1 ) by ω- oxidation of the terminal methyl group on the alkyl chain by oxidation of β or α- oxidation of long- chain molecules that form short -chain sulfonic disconnect benzene carboxylic acid ; ( 2 ) oxidation of the benzene ring to open crack action ; ( 3 ) de- substituted sulfonic acid salt removed by this process . However, these three mechanisms on the role of sequence researchers have not yet reached consensus view . Studies have shown LAS can be degraded under anaerobic conditions .
Most of the LAS aerobic degradation is mainly to increase the dissolved oxygen concentration , can significantly increase the degradation of LAS . Aerobic biodegradation of LAS mainly contains three kinds of mechanism: ( 1 ) by ω- oxidation of the terminal methyl group on the alkyl chain by oxidation of β or α- oxidation of long- chain molecules that form short -chain sulfonic disconnect benzene carboxylic acid ; ( 2 ) oxidation of the benzene ring to open crack action ; ( 3 ) de- substituted sulfonic acid salt removed by this process . However, these three mechanisms on the role of sequence researchers have not yet reached consensus view . Studies have shown LAS can be degraded under anaerobic conditions .
Other effects of coexisting substances
Biodegradation of LAS will be affected by the presence of other pollutants , when the water there are other biodegradable organic pollutants , will produce inhibition of microbial degradation of LAS or catalytic role in some of the water -binding makes the LAS chemically changed thus changing the biochemical degradation of LAS . LAS primary pollutants into the water after the other pollutants combine to form with a certain degree of dispersion of colloidal particles of industrial wastewater and domestic wastewater physicochemical and biochemical characteristics has a significant impact , and produce potentially dangerous.
Biodegradation of LAS will be affected by the presence of other pollutants , when the water there are other biodegradable organic pollutants , will produce inhibition of microbial degradation of LAS or catalytic role in some of the water -binding makes the LAS chemically changed thus changing the biochemical degradation of LAS . LAS primary pollutants into the water after the other pollutants combine to form with a certain degree of dispersion of colloidal particles of industrial wastewater and domestic wastewater physicochemical and biochemical characteristics has a significant impact , and produce potentially dangerous.
没有评论:
发表评论