Lead: What kind of papers will environmental engineering major write? The following are my collected papers on environmental engineering for your reading and reference.
Paper 1: Review on the research of magnetic immobilization technology in environmental engineering;
Magnetic solidification technology has been widely used in environmental engineering by virtue of its own characteristics and advantages, and it has a good application prospect from its due effect. On the basis of introducing the types of magnetic solidification technology, this paper introduces its application in the field of environmental engineering for reference only.
Key words:
Magnetic solidification; Environmental engineering; waste gas treatment
Magnetic immobilization technology locates enzymes or microorganisms on magnetic immobilization carriers by physical or chemical methods. After the curing reaction, it can be separated by external magnetic field, while the enzyme or microorganism remains active and can be cured for many times, which has a good application prospect.
1 Curing classification of magnetic carriers
Magnetic nanospheres are commonly used carriers in magnetic curing process, and their classification can be roughly divided into the following categories.
(1) adsorption method, in which the enzyme is immobilized on a carrier such as agarose or porous glass by physical adsorption method. The immobilization method has the advantages of mild immobilization conditions and simple process. At the same time, its carrier has a wider choice space, which can choose both synthetic polymer materials and natural polymer materials. In the process of adsorption, immobilization and purification can be realized, the inactivated enzyme can be activated again, and the applied carrier can also be regenerated.
(2)*** valence method, the reactive group of the carrier and the molecular functional group form a * * * valence bond, which is very firm and has high stability in the application process, and the enzyme rarely falls off. The main disadvantages of this method in the application process are that curing and carrier activation are relatively complicated, and the environment required for the reaction is also very intense. Therefore, in order to obtain immobilized enzyme with good activity, the reaction conditions must be strictly controlled.
(3) Embedding method, which fixes the enzyme in the microcapsule or lattice structure of polymer material, effectively avoids the release of enzyme protein, but in actual operation, the substrate can still contact with the enzyme in the microcapsule or lattice. The biggest advantage of this method is that it is relatively easy to operate, but it only embeds enzyme molecules and will not cause serious damage to biological activity. However, this method is not suitable for substrates with macromolecules. (4) Cross-linking method: cross-linking between proteases is completed by using reagents, so that valence bonds are formed between multifunctional reagents and enzyme molecules, and finally a three-way cross-linking network structure is formed, and enzyme molecules have both external cross-linking and internal cross-linking. In the actual operation, different materials will make the immobilized enzyme have different physical properties.
Application of environmental engineering in magnetic solidification technology
2. 1 environmental detection
The application of immune magnetic separation technology in biology and medicine has been very mature, and it has also been applied to environmental detection in recent years. By applying immune magnetic separation technology, the target microorganism can be separated from the sample. If it is reasonably combined with fluorescence immunoassay and polymerase chain reaction, the detection limit and separation efficiency can be improved. ATP can be combined with immunomagnetic separation technology when detecting the content of Escherichia coli in wastewater. The experimental results show that the whole detection time is less than 60min, and the detection result has high accuracy, so it is a fast and effective detection method. Some scholars have used surface-modified magnetic nanospheres in the process of separating metal ions. The experimental results show that Cu, Co and Pb ions can be extracted in sequence in the solution with the concentration of 10ng/ml and pH=4, and the extraction efficiency is over 90%, which is a good method.
2.2 Waste gas treatment
Magnetic immobilization technology has the advantages of fast reaction speed, high density, easy separation of products and strong toxicity resistance, and is widely used in the field of waste gas treatment. Xuan Qun and other researchers used sodium alginate for curing experiments, and the degradation rate of ferric sulfite oxide exceeded 97%, which achieved good application results. Ma Yanling and other researchers use calcium alginate to immobilize microbial particles to purify waste gas, such as hydrogen sulfide. Experiments show that the removal rate of hydrogen sulfide is over 90%, and the removal effect is good. In addition, Ma Yanling uses activated carbon to adsorb and degrade the oil fume and waste gas produced by Pseudomonas. The experimental results show that when the gas flow rate is less than 8L/h, the oil fume concentration is less than 100mg/L, the volume load is 2.5 ~19.0g/m3 h, and the oil fume residence time is more than 30s, the oil fume interpretation efficiency of the active reactor is over 95%.
2.3 wastewater treatment
Some scholars are trying to combine magnetic technology with solidification technology in the process of sewage treatment, using magnetic substances as the carrier of enzymes or microorganisms in the solidification process, and treating microorganisms and sewage through its magnetic field and efficient separation, which makes up for the shortcomings of traditional wastewater treatment that microorganisms are difficult to treat and microbial water is separated, and explores a new way of wastewater treatment. After a series of treatments, magnetic nanospheres can carry functional groups, which improves the immobilization ability of carriers to microorganisms to a certain extent. Immobilized microorganisms attached to magnetic carriers can improve their efficiency and speed in wastewater treatment. At the same time, they have the advantages of magnetic treatment in wastewater treatment, that is, they have strong magnetic response in the presence of external magnetic fields, so the carriers can be easily separated from the reaction system and the treatment effect is good.
Some scholars immobilized horseradish peroxidase on magnetic microspheres. In the process of enzyme immobilization, the maximum immobilized amount of enzyme can reach 3.35 mg/g. The wastewater (including phenolphthalein) was treated in the reactor, and the components of the wastewater were treated during the experiment. The kinetic parameters of free enzyme Km and immobilized enzyme Vmax were 224μmol/L and 37 1 μ mol/L, respectively. Some scholars also use magnetic activated sludge to treat wastewater from dairy production, mainly to treat ammonia nitrogen and organic matter in wastewater. Relevant experiments show that the treatment rate can reach 98% and 92% respectively, and with the development of science and technology, the treatment rate will be further improved, which shows that it is an efficient treatment method. Some scholars have also studied the bacteria-fixing effect of functionalized silicon-coated mesoporous magnetic carrier, mainly analyzing the factors such as pH value, treatment time and treatment temperature, and at the same time, it is necessary to compare the results with other carriers in the research process. The experimental results show that at 30℃, the vibration speed in the shaking table is 200r/min, and the immobilized bacteria culture for 24 hours is the best. In the process of urban sewage treatment, the carrier with immobilized bacteria is used for 24 hours treatment. The main treatment process should be carried out under the optimal conditions of pH=7 and dosage of 0.5g In this environment, the COD removal can exceed 83%, and the acid cleaning is completed with HCL solution with pH=2.
Putting the immobilized enzyme on the magnetic carrier into the magnetic field stabilized fluidized bed reactor can simplify the operation of the whole system in the reaction process and is suitable for large-scale production. By applying magnetic field, the movement direction and mode of immobilized enzyme can be properly controlled. By replacing the traditional mechanical stirring method, the stirring can be made more reasonable and the catalytic efficiency of immobilized enzyme can be further improved.
Some scholars use nano-magnetic powder to magnetize bacterial biofertilizer to treat slaughter wastewater. The treatment results show that the mixed solution of magnetic biological flocculation mud and water can be quickly separated by this process, and the precipitation can be completed in only 65438±05min during the treatment. Magnetic powder and magnetic field can promote microbial metabolism, improve sludge activity and wastewater treatment effect. Through a large number of experimental results, it can be found that the removal rates of SS, COD and NH3-N3 chemicals can reach 92%, 96% and 87% respectively. The treated water quality is much higher than the discharge standard, with strong impact load resistance and good application prospect.
3 Conclusion
Magnetic solidification technology is widely used in biology, medicine and other fields because of its own characteristics and advantages, and its application is gradually mature, but its application in environmental engineering is still in the development stage. Therefore, it is necessary to strengthen the application research of magnetic solidification technology in the field of environmental engineering, expand its application scope, and gradually develop the research results from the experimental stage to the application stage, so as to further improve China's environment.
Paper 2: Teaching reform of chemical pollution in environmental engineering specialty Chemical pollution and ecology is a science to study the interaction between pollutants in the ecological environment and the surrounding ecological environment, and it is an important professional course of environmental engineering specialty. Chemical Pollution and Ecology is a comprehensive course with strong reality and practicality. In view of the teaching of chemical pollution and ecology, we have made some explorations in the teaching reform and practice for many years and formed some ideas.
First, the analysis of curriculum characteristics
Chemical pollution and ecology is a comprehensive professional course for third-year students majoring in environmental engineering. This course covers a wide range of content and scope. Therefore, students need to have basic knowledge related to this course before learning this course. Students should have a deep understanding of not only organic chemistry and inorganic chemistry, but also ecology and environmental science. In the course of this course, students can further master the interaction law between chemical pollutants and ecological environment on the basis of previous knowledge, and can analyze the actual pollution process according to what they have learned and put forward specific prevention and control measures. In the learning process of this course, students should not only learn all kinds of theoretical knowledge, but also be able to carry out relevant verification and design experiments to realize the combination of theory and practice. At the same time, the study of this course can stimulate students' interest in learning, broaden their horizons and lay a certain foundation for further study of other courses in environmental engineering.
Second, the design of teaching content
The main research content of the course of chemical pollution and ecology is the interaction between chemical pollutants and ecological environment, analyzing the actual pollution process and putting forward specific prevention measures. An important feature of this course is that it involves interdisciplinary subjects, including the basic concepts and principles of chemistry, environmentalism and ecology. This course involves a lot of content, but the course hours are limited. Therefore, in the design of course teaching content, we should take these actual situations into account, avoid the duplication of the content of this course with that of other related courses, and focus on the core content of this course. The main content of this course is to explore the structure and function of ecosystem according to the basic principles of ecology, and to study in detail the sources, distribution, circulation, migration and transformation of non-metallic pollutants, heavy metal pollutants and organic pollutants, as well as their effects on ecosystem and prevention methods. At the same time, in the teaching process, it is necessary to introduce the latest development trend of this subject through words and audio-visual pictures, so that students can understand the latest research results, which can enrich and enrich the teaching content.
Third, the use of teaching methods in the teaching process
In the teaching process of this course, it is found that it is difficult to meet the requirements of cultivating students' ability by teaching the teaching content entirely by teachers. This teaching method is not conducive to giving full play to students' subjective initiative and cultivating students' innovative thinking. Therefore, it is necessary to improve the teaching mode in the teaching reform, which can not only play the leading role of teachers, but also mobilize the enthusiasm of students, thus improving the teaching effect. At the same time, different chapters have different specific contents in the teaching process, so different teaching methods can be adopted for different contents to improve teaching efficiency. In the teaching process of chemical pollution and ecology, the following teaching methods are adopted. The first method is teaching method, which is the most basic method in the teaching process. This method is mainly used to tell the basic principles and concepts. In the teaching process, teachers can not only teach the course content, but also tell some related contents in combination with their own scientific research process, so that students can master more subject knowledge. The second method is classroom questioning method. Questioning in class can enliven the classroom atmosphere and mobilize students' ability to think positively. Through active thinking, students' understanding of the key points and difficulties of the course can be strengthened, and the process of analyzing problems can be clear and organized. At the same time, students can also ask questions in class to consolidate their mastery of what they have learned. The third method is class discussion, which is a better teaching method. With the deepening of quality education, classroom discussion has been used more and more. This method can enliven the classroom atmosphere, fully mobilize students' learning enthusiasm, and is conducive to cultivating students' subjective initiative in the learning process. Students can find problems in class discussion and then solve them through discussion. This is a cooperative learning process. Through this analysis and summary of the thinking process, students can experience the process of independent inquiry. In the process of classroom discussion, in order to achieve better teaching effect, students need to fully think about the problem. In order to give students enough time to think independently, we can introduce the main contents and questions of the next class in advance, and learn the course content through classroom discussion under the guidance of teachers. The fourth method is case teaching method. Teachers should pay attention to the use of cases in the teaching process. By discussing some environmental pollution problems and events through practical cases, students can learn to analyze the actual situation by using basic principles, deepen their understanding and mastery of the knowledge they have learned, and at the same time, they can keep abreast of the research hotspots and the latest scientific research achievements in this field.
Fourthly, the application of multimedia teaching.
Multimedia teaching method is a new teaching method with the development of computer multimedia technology, and it is an important auxiliary means of traditional blackboard writing teaching method. Multimedia teaching method and blackboard writing teaching method have their own advantages and disadvantages. According to the characteristics of environmental pollution and ecology course and environmental engineering specialty, this course adopts multimedia teaching method combined with blackboard writing teaching method for classroom teaching. In the process of multimedia teaching, the amount of information in classroom teaching can be greatly increased. For example, some charts can be displayed quickly through pictures, so that more time can be spent on the analysis of charts. At the same time, some abstract theories and concepts can be displayed intuitively by using multimedia technology, and the organic combination of perceptual knowledge and rational knowledge can be realized. For example, some abstract concepts and processes can be told through animation. Therefore, the use of multimedia teaching methods can improve students' interest in learning this course, help students understand and master what they have learned in class, and thus improve the classroom teaching effect. Of course, multimedia teaching method is only an auxiliary teaching method, and the traditional blackboard number teaching method still has strong flexibility and practicality. For example, teachers gradually deduce formulas on the blackboard, which is more in line with students' cognitive law than multimedia teaching method, and in the application process of multimedia teaching method, it should be combined with traditional blackboard writing teaching method, so as to achieve better teaching effect.
Fifth, appropriately increase practical content.
The course "Chemical Pollution and Ecology" is very realistic and practical, and practical teaching activities should be carried out. First of all, students should be able to operate confirmatory experiments and operate independently with experimental equipment under the guidance of teachers. By observing various experimental phenomena during the experiment, they can further deepen their understanding and mastery of theoretical knowledge. In addition, students are encouraged to carry out innovative and designed practical projects, such as asking students to put forward research topics from some environmental pollution problems, consulting domestic and foreign literature related to this research topic, and then discussing and determining the research plan, and conducting experiments under the guidance of teachers. This specific scientific research practice can improve students' ability to integrate theory with practice, and at the same time consolidate the knowledge learned in class.
Sixth, change the way of course performance evaluation.
Achievement evaluation is an important aspect of the teaching reform of chemical pollution and ecology. In the process of rating, we need to pay attention to four aspects. The first aspect is the evaluation of students' basic theoretical knowledge of curriculum, which is carried out by means of written examination papers. In the examination process, the method of separating teaching from examination is adopted to prevent teachers' tendency in the process of setting questions. In this way, teachers' teaching effect and students' academic achievements can be evaluated more objectively. At the same time, the process of marking test papers adopts the way of running water marking, and each teacher can analyze the students' answers, thus evaluating the teaching effect more objectively. The second aspect is the evaluation of students' attendance and homework, the third aspect is the performance of students in practice, and finally, students should pay attention to their own understanding of chemical pollution and the development of ecology, as well as the application of some basic principles they have learned in their own professional fields.
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