Various problems of traditional cast-in-place buildings, such as heavy energy consumption, severe environmental pollution, and low labour productivity, have hindered the development of the construction industry. Prefabricated buildings have a direct bearing on national economic development and transformation of people’s lifestyles because of their high economic, environmental, social, and safety benefits. The technological research and development level for prefabricated buildings and system policies in China are still in the initial stage, and the environmental performance and influencing factors of prefabricated buildings limit their large-scale implementation. The literature in developed countries regarding the environmental performance and influencing factors of prefabricated buildings was first reviewed in this study. Community A in Zhengzhou City, Henan Province was used as the case study. AHP (Analytic Hierarchy Process) was applied to measure the factors influencing the environmental performance of prefabricated buildings, and policy suggestions were proposed to improve their environmental performance. Results indicate that developed countries tend to construct prefabricated buildings in large areas because of their remarkable economic, environmental, social, and safety benefits. Measurement results of Community A in Zhengzhou City, Henan Province show that the main environmental pollution factor of prefabricated buildings is waste discharge, accounting for 40%, followed by noise pollution, energy consumption, and dust pollution. The environmental performance of prefabricated buildings can be improved by promoting their development, reducing their environmental pollution, establishing a standard prefabricated concrete system, enhancing the environmental standards for buildings, expanding the application scope of prefabricated concrete, encouraging environmental technology innovation of buildings, cultivating prefabricated building bases, and strengthening environmental governance of construction sites. The findings will serve as reference in determining the main factors influencing the environmental performance of prefabricated buildings, establishing an evaluation system for the environmental benefits of prefabricated buildings, promoting their improvement and optimized development, and enriching and perfecting an evaluation research system for their comprehensive benefits.

The polyvinyl alcohol/graphene oxide (PVA/GO) hydrogel was prepared. It was confirmed that the adsorption performance of polyvinyl alcohol/graphene oxide hydrogel composite material was improved, and it does not cause secondary pollution. According to adsorption experiments, it was found that PVA/ GO adsorbent with a content of 30 % graphene oxide has the best comprehensive performance. The suitable environment of adsorption was under 25°C, 12-18 h for adsorption time and acidic conditions. The suitable adsorbent dosage was 0.3g and the suitable concentration of the dye was 10 mg/L.

The purpose of this study was to evaluate the performance of anaerobic digestion of organic fraction of municipal solid waste to biogas in a mesophilic (32°C) continuous digester at a total solid concentration (TS) of 12%. The digester was operated with different organic loading rates and constant retention time. The performance of the reactor was evaluated using parameters like pH, volatile fatty acid (VFA), alkalinity, chemical oxygen demand (COD), total organic carbon (TOC), ammonia-N and biogas yield. During the reactor’s start-up period (first phase), the process is stable and there is no inhibition occurred. In the second phase, the reactor was fed in continuous mode with different organic loading rates and constant retention time. The highest volatile solid (VS) degradation of 65.9%, with specific biogas production of 368 L.kg-1 VS fed was achieved with organic loading rate (OLR) of 3.1 kg VS.m-3.d-1 and a retention time of 30 days.

A sudden leak of phenylethylene is an urgent issue for the surrounding environment. To mitigate its negative effect, the decontamination efficiency of phenylethylene on an activated carbon (AC)-based adsorbent was investigated. Factors such as the particle size and the temperature, that could affect the adsorption ratio, were explored. Meanwhile, the efficiency of AC, pretreated with different KMnO4 and NaClO concentrations, was examined. It was proven that the decontamination efficiency was higher for the 300-mesh AC compared to the 200-mesh AC. The introduction of the oxidizer, KMnO4, had a negative effect on phenylethylene adsorption. Nevertheless, the NaClO-modified AC showed a positive influence on phenylethylene removal, while its decontamination gradually improved with the increase of the NaClO concentration. It was also found that the adsorption rate of phenylethylene was ascended with the temperature rise. After 1 h of adsorption with AC heated to 200°C, no phenylethylene desorption was observed.

With the economic growth and massive industrialization, the air quality of China in general and industrial regions in specific has saturated with different health hazard pollutants. Among the pollutants, PM2.5 is posing some serious threats to the society. In this study we evaluated the correlation between PM2.5 concentration and 12 different meteorological, vegetation and topographical factors in Beijing, China. We used the Difference Index (DI) method and dark pixel method to retrieve the PM2.5 concentration of 30m and 1km spatial resolution. Spearman correlation analysis method was used to analyse the correlation between PM2.5 concentration and three types of 12 factors. The results showed that the forest land can play a major role in decreasing the PM2.5 concentration in the air, as in this study a significant drop of (18.78%) was observed in PM2.5 concentration in the regions having coniferous forest. Moreover, the PM2.5 reduction rate was positively correlated with forest vegetation coverage (FVC). Our results demonstrated that relative humidity, air pressure and water vapour pressure were positively correlated with PM2.5, while air temperature and wind speed were negatively correlated. The altitude and slope showed a weak negative correlation with PM2.5 concentration, while, aspect was very weakly correlated with the PM2.5 concentration. The findings of this study could help design the urban green space planning and air pollutioncontrol in the heavily populated urban ecosystems.

Rapid depletion of fossil fuels and escalating crude oil prices led the researchers to ascertain alternative feedstock as a substitute for mineral diesel. Biodiesel produced from non-edible sources was one among them. In the present investigation, palm stearin wax, a residue of palm oil extraction was used as a value-added feedstock for the production of biodiesel. Palm stearin biodiesel (PSBD) was derived from this feedstock using single stage transesterification process involving methanol and sodium hydroxide as a catalyst. PSBD was blended with mineral diesel at 20% (D80PSBD20) and 50% (D50PSBD50) in volume basis. The effect of variable compression ratios on the performance and emission phenomena of direct injection CI engine was analysed for test fuel blends. The tests were carried out for compression ratios 17:1, 17.5:1 and 18:1. Among all the fuel blends, D80PSBD20 blend showcased better performance characteristics along with reduced exhaust emissions at compression ratio of 18:1.

The occurrence of caffeine residue in Malaysian waters was successfully studied. The micropollutant abundance was recorded for three selected main rivers namely Terengganu, Ibai and Setiu which are located in Terengganu, Peninsular Malaysia. Surface water samples were taken twice in September and November 2018 from 15 sampling stations. Caffeine residue was determined using the solid phase extraction technique followed by a final analysis using a high performance liquid chromatography-UV detector. Measured concentration levels ranged from 384 to 426 ng/L for both datasets obtained from the two sampling surveys. The ecological risk assessment was calculated to be at low risk ranging from RQ 0.075 to 0.085, while the risk quotients (RQ) of human health risk was recorded below than 0.20 for three life-stage categories. The MaxRI values fall under class II which means that there is a risk of sublethal effects to aquatic organisms.

Agriculture is located at the crossing point between ecosystems and society, where changes in the global environmental conditions affect agricultural activities. The total agricultural area in Abu Dhabi Emirate in 2017 was 749,868 donums. This study had two main objectives; first, to understand how agricultural and livestock production has changed and how these changes are relevant to socioeconomic statuses; second, to assess climate change’s impact on agricultural and livestock production through groundwater characteristics. We distributed and collected 301 surveys throughout the three main regions in the Abu Dhabi Emirate (Abu Dhabi City, Al-Ain City, and Al Dhafrah). The results indicated that approximately 68% of the respondents in Al-Ain agreed that it is currently much easier and more profitable to manage a farm than it was 20 years ago. Further, 39% of the farmers agreed that both product quality and quantity have improved over the past 20 years. About 51% of Emirati nationals agreed that production has changed over time. The farmers aged between 51-60 years also agreed that there has been a change in production over time. Half of the farm owners agreed that production has changed, while a majority of the workers provided neutral responses on this topic. While a number of both owners and workers agreed that both production and income levels changed, more respondents disagreed than agreed that these changes had occurred. Finally, the farmers aged between 51-60 years agreed more that the groundwater levels and quality had changed over the past 20 years.

Graphene oxide (GO) and acrylamide (AM) were polymerized and cross-linked to form a composite aerogel. The microscopic properties and thermal stability of the composite aerogel were characterized by infrared spectroscopy, thermogravimetric instrument and scanning electron microscopy. The adsorption properties of the composite aerogel were tested. The effects of temperature, GO/AM ratios, pH values, feed amounts, dye liquor concentrations and times on the adsorption properties of composite aerogels were investigated. The results showed that under the same experimental conditions, the more the aerogel dosage and the longer the adsorption time, the better the adsorption performance of the composite aerogel on the active yellow dye liquor; the temperature had little effect on the adsorption of the dye liquor. The gel had the greatest adsorption effect under acidic conditions. The pH was 0.99, the dosage was 0.25g, the concentration of the dye solution was 40mg/L, and the adsorption rate reached 65.51?ter adsorption for 24 hours.

Zhuzhou is an important part of the Changsha-Zhuzhou-Xiangtan city group in southern China. To grasp the economic benefits of urban wetland resources value in Zhuzhou City, strengthen wetland conservation and utilization, and ensure the sustainable development of cities, this paper takes Zhuzhou 2016 wetland remote sensing image interpretation map and multi-source data as the foundation, and build urban wetland ecosystem service evaluation system. Through deduplicate double counting, this paper evaluates the value of urban wetland ecosystem service in Zhuzhou City employing shadow project method, replacement cost method, travel cost method, conditional value method and other economic value evaluation methods. The results indicate: (a) The total value of urban wetland ecosystem services is $1,527,908,900 in 2016. (b) The ultimate value of urban wetland services ranked as follows: water storage regulation value ($539,566,265), climate regulation value ($424,930,361), tourism recreation value ($174,543,328), water supply value ($133,183,901), biological product value ($121,987,952), atmospheric composition regulation value ($92,111,687), soil erosion prevention value ($15,799,608), water purification value ($14,598,298), and aesthetic heritage value ($10,075,346); (c) The value of different types of wetlands ranked as follows: paddy fields ($526,111,672), riverine wetland ($526,111,672), ponds ($329,628,343), reservoirs ($149,275,241), wastewater treatment plant ($207,831/a); (d) The value per unit area of different types of wetlands ranked as follows: reservoirs ($240,919/ha), riverine wetland ($236,627/ha), pond ($145,693/ha), paddy fields ($26,551/ha) and wastewater treatment plant ($17,003/ha). The evaluation results reveal the great contribution of urban wetland system service to the Zhuzhou city with numbers, that not only provides data basis for wetland conservation and management but also provides a reference for the refined evaluation of urban wetland ecosystem service value.