Organic substrate degradation, what is biodegradation?

Organic matter is broken down into inorganic matter.

Biodegradation refers to the dissolution, enzymatic hydrolysis, and cell phagocytosis of materials in living organisms, which is continuously excreted from the body during the process of tissue ingrowth, completely replaces the position of the implanted material after repair, and the material has no residual properties in the body.

Metal implants are a class of metal materials that gradually corrode in the organism until they are completely dissolved in the process of assisting and completing the repair of biological tissues, and the corrosion products of the material will not produce or produce a slight host reaction to the organism.

Therefore, the main components of biodegradable metal materials should be basic metal elements that can be excreted by organisms through metabolism and have a certain corrosion rate in organisms.

Natural materials refer to macromolecules that naturally exist in animals, plants or human bodies, such as cellulose, chitin, starch, lignin, alginic acid and other natural polysaccharide materials; Natural protein materials such as collagen and fibrinogen.

Synthetic biodegradable polymer synthetic degradable absorbable biopolymer materials are reproducible and can be produced in large quantities by controlling process conditions, and a wide range of properties can be obtained through simple physical and chemical modification to meet different needs, so the application of synthetic degradable and absorbable biopolymer materials is more extensive. The main ones are poly-hydroxy acids, polyanhydrides, poly-amino acids and aliphatic polyesters.

It refers to the dissolution, enzymatic hydrolysis, and cell phagocytosis of materials in living organisms, which is continuously excreted from the body during the process of tissue ingrowth, completely replaces the position of the implanted material after repair, and the material has no residual properties in the body. Biodegradable metal medical materials refer to the process of metal implants assisting and completing the repair of biological tissues.

A class of metallic materials that gradually corrode in living organisms until they are completely dissolved, and the corrosion products of the materials do not produce or produce a slight host reaction to the living organism.

Biodegradable non-metallic materials.

The decay of the structure or substance produced by bioceramics in the physiological environment, and its products are absorbed and utilized by the body or excreted from the body through the circulatory system, which is called the biodegradation of ceramics.

After the biodegradable or bioresorbable ceramic material is implanted into the bone tissue, the material is dissolved and absorbed by the body fluid or excreted by the metabolic system, and finally the defective part is completely replaced by the new bone tissue, and the implanted biodegradable material only plays the role of a temporary scaffold. In the body, part of it is excreted from the body through a series of biochemical reactions, and part of it participates in the formation of new bone.

At present, the degradable and absorbable bioceramics that are widely used and studied mainly refer to calcium phosphate bioceramic materials, which include tricalcium phosphate, tetracalcium phosphate and hydroxyapatite and their mixtures, etc., which can be partially or fully absorbed after a period of time after being implanted in the body.

At present, biodegradable plastic bags are more widely used in biodegradable plastic bags, also known as biodegradable plastic bags, which refer to the mineralized inorganic salts of carbon dioxide (CO) or methane (CH), water (HAO) and the mineralized inorganic salts of the elements contained in water and new biomass under specific conditions such as composting conditions or anaerobic digestion conditions or aqueous culture mediums. It can be divided into two types: bio-based and petroleum-based.

Bio-based degradable plastics include: polylactic acid (PLA), regenerated cellulose, starch plastics, polyhydroxy fatty acid ester polymers (PHAS), etc.

Petroleum-based biodegradable plastics include: polybutylene succinate (PBS), polycaprolactone (PCL), polyglycolic acid (PGA), carbon dioxide degradable plastics (generally referring to carbon dioxide and epoxy propylene ring polymer PPC), and a class of copolyesters, such as polybutylene adipate terephthalate (PBAT), polyadipate butylene succinate copolymer (PBSA).

At present, the most commonly used is made of polylactic acid (PLA) and polyadipate butylene terephthalate (PBAT), which are mainly composed of starch or calcium carbonate.

Biodegradation refers to the transformation of organic matter into simple inorganic matter by microorganisms. The excrement and dead bodies of various organisms in nature are transformed into simple inorganic substances by the decomposition of microorganisms. Microorganisms can also degrade synthetic organic compounds.

For example, through oxidation, aldrin is converted into dieldrin; Nitro-containing insecticides are reduced to amines through reduction; The ring-cracking phenomenon of aromatic groups is also a common reaction of microbial degradation.

Microbial degradation makes it possible to recycle the elements of life, degrading various complex organic compounds, thereby maintaining a virtuous cycle of the ecosystem.

Refractory organic matter refers to organic compounds that are not easily decomposed by microorganisms or other chemical reactions in the natural environment. These compounds are generally highly stable and low biodegradable, so they can persist in the environment for long periods of time and pose a potential hazard to the environment.

1.Industrial wastewater: Industrial wastewater contains a large number of various chemicals, such as solvents, dyes, plastics, etc., which can produce pollution sources that are difficult to decompose.

2.Pesticides and fertilizers: Pesticides and fertilizers contain many complex chemicals, some of which may remain in soil or groundwater and accumulate over time.

3.Petroleum products: Petroleum and its derivatives (such as gasoline, diesel, etc.) also contain many compounds that are difficult to decompose, which will have a serious impact on soil and groundwater in the event of a leakage accident.

4.Household waste: Municipal landfills also contain many materials that cannot be broken down quickly, such as plastic bags, foam boxes, etc.

5.There are some naturally occurring special structural systems (such as dioxins) with strong durability and toxicity in nature, which are also affected by natural disasters such as climate change and volcanic eruptions, which further exacerbate the increasing trend of their numbers.

In short, the problems caused by the interaction of human activities and natural phenomena have attracted widespread attention and require effective measures to deal with them. Sedan chair.

Influencing factors of organic matter degradation: temperature, humidity, pH, composition of organic matter. Take, for example, the degradation of organic matter in a landfill.

1. Temperature: The temperature range of microbial growth is very wide, about -5 85, and can be divided into low temperature type, medium temperature type and high temperature type according to different microbial growth temperatures. The degradation of garbage in landfills generally occurs in the medium and high temperature sections, and the optimal temperature of the medium temperature type is 18 35 and the maximum temperature is 40 45. The optimum temperature for the high-temperature type is 50 60 and the maximum is 70 85.

Studies have concluded that 30 to 40 in landfills is the most suitable temperature for microbial gas production.

2. Humidity. The existence of juvenile water is the basic condition for microbial life activities and garbage degradation. The water in the landfill has a wide range of tolerances, generally 25% to 70%.

When the moisture content is high, it is easy to produce foul odor; When the moisture content is low, it is not conducive to the microbial degradation of garbage. The optimal moisture content of garbage degradation is 50% to 60%, and the higher the moisture content, the higher the gas production rate.

3. pH value. The degradation of organic matter in landfills is done by microorganisms, and methanogens, which are essential for waste degradation, have strict pH requirements, with an optimal pH range.

4. Composition of organic matter. In the process of garbage degradation, in order to meet the growth needs of microorganisms, sufficient C, N and P must be provided in the garbage, and generally when C N is in (10 20):1, the removal rate of organic matter is the largest.

If the C N is too high, the N required by the bacteria is insufficient, which will lead to the accumulation of organic acids and inhibit the growth of methanogens; If the CN is too low, it will lead to the accumulation of salts, which will increase the pH value, and when the pH value exceeds 8, it will inhibit the growth of methanogens.

Refractory organic matter usually refers to organic chemicals that are difficult to be decomposed by biological action under natural conditions.

Organic matter is degraded by microorganisms and converted into inorganic matter, and because inorganic matter is synthesized into various organic matter through life activities, this is the basic cycle of biogeochemistry in nature. Synthetic detergents, organochlorine pesticides, polychlorinated biphenyls and other compounds are difficult to biodegrade in water, and fats and oils in nitrogen-free organic matter are also refractory substances, which are often gradually concentrated through the food chain and cause harm; During production, use and after use, it will enter the water body through various ways and cause pollution. The persistence of refractory substances in the environment and the dispersion of a wide area have a great impact on the environment and ecology.

Therefore, it has always been an important link in the vicious circle of environmental pollution and ecological environment.

Internationally recognized.

Polyethylene (PE).

Polyvinyl chloride (PVC).

Polypropylene (PP).

Polystyrene (PS).

Polymethyl methacrylate (PMMA).

Urea-formaldehyde plastic (voltage).

Polytetrafluoroethylene (PTEE).

There may be.

Refractory organic matter is not easily biodegradable, they will continue to accumulate in natural environments such as water bodies and soils, and then enter the organism through the food chain and gradually enrich. They not only endanger the health of living beings, endanger the entire ecosystem, but eventually enter the human body and endanger human health. At present, the treatment methods of refractory organic matter wastewater at home and abroad mainly include physical and chemical pretreatment technology and biological main body treatment technology.

In layman's terms, it is organic matter that cannot or is difficult to decompose into inorganic matter under natural conditions.

For example, most plastics and so on.