Carbon dots could significantly change the property of a normal material and have received wide attention in the recent decade. In this research, glucose as a carbon source, carbon dots decorated medical stone (CD-MS) was successfully synthesized for efficient adsorptive removal of organic pollutants. Pyrolytic temperature and glucose concentration for the adsorbent preparation were proved to have a significant impact on the adsorptive performance. The optimal pyrolytic temperature and glucose concentration were found to be 300°C and 0.5 M, yielding the optimized adsorbent 0.5CD-MS-300 superior to other carbon dots decorated MS. Surface morphology analysis demonstrated that the carbon dots were successfully immobilized on the surface of MS while the atomic ratio of C increased from 2.6% of the raw MS to 11.25% of the 0.5CD-MS-300. Three organic pollutants including p-nitrophenol, orange II and methylene blue with different charge properties were employed to explore the adsorptive performance of the 0.5CD-MS-300. The results indicated that the surface of 0.5CD-MS-300 was negatively charged while carbon dots had significantly improved the adsorption capability of the raw MS. As such, the resulting adsorbent 0.5CD-MS-300 can be considered as a powerful adsorbent for the removal of some organic contaminants from wastewater.

Emerging contaminants (ECs) have been detected recently in many water bodies across India. Studies have found the presence of ECs in surface water, groundwater, stormwater, treated wastewater, treated industrial effluent, bottled water and snow from glaciers in Indo-Chinese border which contaminate water bodies. The surface water recharges the groundwater, thereby the ECs make their way to deep water aquifers. The soil also gets contaminated and plants can uptake ECs. These micropollutants can cause adverse ecological and human health effects. Antimicrobial resistance of bacteria to commonly used antibiotics has been observed in India. An exhaustive review of emerging contaminants in Indian waters and their treatment technologies has been carried out. Antibiotic-resistant genes can be easily transferred resulting in a plethora of antimicrobial-resistant bacteria which can cause devastating effects on human health. Conventional biological treatment is not capable of removing ECs completely. Advanced oxidation processes using ozonation and visible light active photocatalyst are a sustainable solution for the removal of most ECs. Hence, it is of utmost importance to monitor the presence of ECs in the water environment and develop treatment technologies for its removal.

Changes of total nitrogen (TN), organic matter, microbial metabolic activity, aerobic denitrifying bacteria and aerobic denitrifying genes (nirS and nirK) in water and surface sediments under mixing aeration were studied in Heihe Jinpen Reservoir. Results showed that compared with the control area, the total nitrogen concentration of water and surface sediments in the enhanced area decreased by 29.7%~49.2% and 17.9%. Metabolic activity of microorganisms increased by more than 14%, the utilization rate of carbon source increased by 30% and the McIntosh diversity index of microorganisms increased by 20%. The number of aerobic denitrifiers and genes of aerobic denitrifiers was also increased by 20%. Illumina high-throughput DNA sequencing results showed that the proportion of aerobic denitrifiers such as Acidovorax increased from 0.01% to 0.15%, showing an increase of 15 times. The production practice showed that mixed aeration can improve the metabolic activity and denitrification characteristics of indigenous aerobic denitrifiers, providing theoretical support and technical guarantee for denitrification and carbon removal of slightly polluted source water.

To study the characteristics of air quality and the relationship between air quality and weather factors, based on daily meteorological data from 2016 to 2019 in Beijing using information diffusion technology, the probability distribution of air quality index in different seasons and the development trend of air quality have been studied, and the relationship between weather factors and air quality discussed. The results show that: 1) According to the air quality, the order of the four seasons is summer, spring, autumn and winter. In summer, the frequency of moderate air pollution and above is about 2.54%, and the frequency of serious air pollution is about 0%. In winter, the frequency of moderate air pollution and above is 17.83%, and the frequency of serious air pollution is 2.93%. 2) The air quality of Beijing has been improving in recent years, which shows that with the strengthening of air pollution control efforts, certain results have been achieved. 3) Quantitative analysis of the relationship between winter air quality index and temperature and wind in Beijing shows that the degree of air pollution in winter increases with the increase of temperature and decreases with the increase of wind force. The frequency of mild air pollution and above is about 8.91% when the daily maximum temperature is below 0°C and 48.78% when the daily maximum temperature is above 9°C. The frequency of mild air pollution and above is about 45.17% when the daily maximum wind force is level 0, and 20.89% when the daily maximum wind force is level 3 and above. Examples show that the information diffusion technology can make full use of the location information of the sample points by transforming the traditional sample data points into fuzzy sets, and achieves good results in frequency statistics and trend fitting. The model established in this paper has the value of popularization and application.

Raw kaolinite clay collected from Ire-Ekiti, Ekiti State, Nigeria, was used to adsorb some heavy metals (Pb, Cr, Ni and Cu) from their aqueous solution through batch experiments. Adsorption studies were performed at the different temperatures, concentration and time to determine the kinetics, isotherm and thermodynamic properties of the adsorption processes. The adsorption thermodynamic properties showed that sorption of Cu, Cr and Ni on the raw clay was exothermic, while adsorption of Pb was endothermic. The negative values of ?G for Pb adsorption revealed the feasibility and spontaneity of the adsorption process while the positive ?G values for Cu, Cr and Ni sorption showed non-spontaneity of the adsorption process. Langmuir, Freundlich and Elovich isotherms were applied to explicate the nature of adsorption process, while Pseudo-first-order (PFO), Pseudo-second-order and Elovich kinetics were applied to literarily determine the adsorbate-adsorbent interaction. Pseudo-second-order kinetics was the best fitting kinetics for adsorption of the metals on the raw clay.

Microtopographies affect large portions of the Chinese Loess Plateau after years of water erosion. Vegetation restoration has proven to be an effective way to conserve water and soil, however, studies of the influence of microtopography on naturally recovered vegetation on the Chinese Loess Plateau have long been absent. The objective of this study was to determine the influence of microtopography on the vegetation structure and plant diversity of naturally restored vegetation and compare the soil physicochemical properties of different microtopographies with those of undisturbed slopes on the Loess Plateau. We identified five types of microtopographies that are mainly shaped by runoff in the study area and examined vegetation structures, plant diversity, soil nutrients, and soil water storage compared with undisturbed slopes. The results show that vegetation communities on loess slopes are still in an early successional stage after 14 years of natural recovery. Vegetation diversity was significantly different among microtopographies. Four types of microtopography have better soil conditions for vegetation restoration; scarps are the exception. Our results suggest that microtopographies can create some better condition plots for precision designed artificial restoration of vegetation, which is necessary to accelerate the succession process on the Loess Plateau.

Wetlands are amongst the most productive ecosystems of the Earth. The system includes diverse features in terms of components, functions and attributes. Wetland ecosystems are essential to human well-being (Finlayson et al. 2005). A substantial body of evidence demonstrates that wetlands can deliver a great variety of benefits to human society (Ghermandi et al. 2010). Up to 87% of the global wetland resource has been lost since 1700. The planet is losing wetlands three times faster than natural forests. Tourism is one of the significant tools to enhance and support environmental conservation. According to UNWTO, sustainable tourism means putting the principles of sustainable development, set out at the Rio Earth Summit in 1992, into practice in tourism. Deepor Beel is a permanent freshwater lake and the only Ramsar site in Assam which is experiencing adverse human activities; filling of wetlands for habitation purpose, cutting the sides of wetlands, pollution, fishing and killing of migratory birds. Degradation of water quality, sedimentation in the lake surface, deforestation activities in and around the Beel area has increased the importance of conservation and restoration of the Beel. Presently, Deepor Beel is a degrading Beel, facing threats due to urban encroachment and its illegal uses. Therefore, the research questions for this study are- (i) What are the causes and effects of deterioration of the wetland ecosystem? (ii) How to manage the wetland ecosystem through ecotourism development? The study aims to conserve urban wetlands to enhance eco-tourism and have a balanced urban development of Guwahati. To understand the potentiality of eco-tourism in Deepor Beel in Guwahati, the objectives are to understand the importance of urban wetland ecosystem and its present status, to assess the development initiatives in terms of tourism development by government and private sectors in Guwahati, to analyse the socio-economic and governance aspects of the wetland management and tourism in Guwahati and finally to suggest strategies or measures to enhance ecotourism-based wetland development. Primary and secondary data are used in the study through field study and secondary data collection from various organisations. Ecotourism opportunity spectrum is an analysis done to understand the suitability of the wetland for ecotourism development. To understand the anthropogenic impacts of human activity, water quality index, spatial pattern analysis, species diversity index, correlation analysis, carrying capacity analysis, Kuppuswamy’s socio-economic scale, Karl Pearson correlation, vulnerable economic index, WTP-Demand Curve, SWOT analysis and Pralong’s method is used to derive the potentiality of the wetland for ecotourism. Tools like Arc GIS, SPSS, MS Excel, Google Sketch Up and Google Earth have been used for the various analyses of the study. The study would find its application in the field of ecotourism development at the state level which would contribute to the growth of GDP to the nation. The initiatives were taken under ecotourism that incorporates policies and strategies at the organizational level, spatial planning, local community level that would also benefit the local community by generating employment as well as conserving the richness of the biodiversity of the lake. The findings and proposals of the study can be a helpful strategy to develop an appropriate policy for tourism to be beneficial to both the economic benefits of the state and empowerment of the local people.

Observational studies aiming to elucidate the differences in butterfly fauna along altitudinal gradients in Binsar Wildlife Sanctuary were carried out during 2014-2015. The study revealed a total of 2591 individuals belonging to 46 species and 35 genera under six families of butterflies. Four species under legal protection were also recorded. Family Nymphalidae was the most dominant with 22 species followed by Pieridae (12 species), Lycaenidae (4 species), Papilionidae, Riodinidae (3 species each) and Hesperiidae (2 species). Higher values of species richness, abundance and diversity were recorded for transects at the low altitudinal site. Species such as Aglais caschmirensis (Fruhstorfer), Pieris canidia indica Evans, Pieris brassicae Linnaeus and Byasa polyeuctes letincius (Fruhstorfer) were most abundant, while Dodona ouida Hewitson, Udara dilectus Moore, Aulocera padama Kollar, Talicada nyseus (Guérin-Méneville) and Argynnis childreni (Gray) accounting for 1.38% of the total individuals of butterflies, were least abundant species during the study period. Results of the study on diversity and distributions of butterflies are preliminary ones which would help in strengthening the biodiversity status of the Binsar Wildlife Sanctuary.

With astounding advances, China expressway construction has caused inevitable environmental destruction around the construction projects. A series of expressway construction-induced environmental problems is caused by the noise pollution of machinery and equipment in expressway construction, atmospheric pollution caused by fuel consumption, soil contamination caused by abandoned waste materials and gases generated by asphalt mixture during road paving, and increasing traffic volume. In this study, the literature regarding expressway construction-induced environmental pollution was combined by taking Changyu (Changchun-Yulin Lalin River) Expressway as an example. The impacts of expressway construction on the ecological environment were analyzed, and feasible treatment measures were proposed. Results show that the expressway construction in various countries across the globe aggravates the regional ecosystem damage unavoidably to a certain extent; The environmental impacts caused by Changyu Expressway are manifested at five aspects, namely, water environmental pollution, vegetation deterioration, heavy metal pollution, water and soil losses, and induction of geological disasters; The environmental impacts of expressway construction can be mitigated by reasonable route selection, strengthening planning and environmental protection, preventing water and soil losses, reinforcing atmospheric pollution detection, reducing sewage discharge, enhancing vegetation recovery, and relieving the impact on animal habitats. The study results serve as an important reference for identifying the sources of expressway environmental risks and lowering the environmental pollution caused by expressway construction to an acceptable level.

Construction of pavement layers on subgrade soil with excellent properties reduces the thickness of pavements and consequently reduces the initial cost of construction. However, construction of pavement on poor soil subgrade like black cotton soil is unavoidable due to several constraints. In such a situation, the enhancement of subgrade properties can be attained by the addition of foreign materials. The worldwide growing usage of cement has led to a larger collection of crystalline silica from the cement manufacturing plants. The disposal of the crystalline silica is extremely challenging and also causes an environmental impact. Hence this waste material can be used for enhancement of the strength of the weak soils. Chemical analysis has revealed that crystalline silica is rich in oxides such as silicon oxide, aluminium oxide and calcium oxide. In this study, the black cotton soil is blended with 8%, 12%, 16%, 18% and 20% crystalline silica by the weight of the dry soil. Laboratory tests, namely, standard proctor compaction test, California Bearing Ratio (CBR) test and Unconfined Compressive Strength (UCC) test were carried out to examine the performance of crystalline silica mixture in black cotton soil. The outcome suggests that a potential increase in crystalline silica content enhances the maximum dry density (MDD). The results also indicate there is a huge potential to use crystalline silica as an admixture to strengthen the black cotton soil. Moreover, the employment of crystalline silica might also benefit the environment and construction cost.