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This study explores a bibliometric approach to quantitatively assessing current research trends on solid waste, by using the related literature published between 1997 and 2011 in journals of all the subject categories of the Science Citation Index. The articles acquired from such literature were concentrated on the general analysis by publication type and language, characteristics of articles outputs, country, subject categories and journals, and the frequency of title-words and keywords used. Over the past 15 years, there had been a notable growth trend in publication outputs, along with more participation of countries/territories. The seven major industrialized countries (G7) published the majority of the world articles, while their article share was being replacing by other countries represented by BRIC countries. An analysis of the title-words, author keywords and keywords plus showed that municipal solid waste and sludge were the major research types of solid wastes and “anaerobic digestion”, “wastewater” and “heavy metals” were recent major topics of solid waste research. Meanwhile, the analysis indicated the analysis technologies, represented by solid-phase extraction and tandem mass-spectrometry, were more and more widely used for solid waste research. Besides, life cycle assessment and health risk assessment were the most two frequently environmental assessment tools used for solid waste research in the 15-year research period.

Municipal solid waste (MSW) management in China draws particular attention as China has become the largest MSW generator in the world. The paper analyzed the growth and development of MSW research productivity in China in terms of publication output as reflected in science citation index for the period 1997–2011. The study revealed that the output of MSW research in China has rapidly increased over the 15 years in contrast with USA. Chinese authors contributed 730 publications out of which 708 were journal articles, 17 reviews, 3 editorial materials, 1 correction and 1 meeting abstract, from 421 institutions. About 13.70 % of publications were contributed by Chinese Academy of Sciences, followed by Tongji University, Shanghai (13.15) and Tsinghua University, Beijing (11.10 %). That impact factors of the top 20 journals publishing most papers were between 0.30 and 4.63. Leading 20 authors in the area of MSW research published at least 13 articles per person. The annual share of publications varied from 0.27 to 20.96 % per year. The share was highest in the year 2009 at 20.96 %. An analysis of the title-words showed that “landfill”, “incineration” and “management” were recent major topics of municipal solid waste research in China. The results could help researchers understand the characteristics of research output and search hot spots of MSW field in China.

Selective loading of spatially separated redox cocatalysts on direct Z-scheme heterojunctions holds great promise for advancing the efficiency of artificial photosynthesis, which however is limited to the photodeposition of noble metal cocatalysts and the fabrication of hollow double-shelled semiconductor heterojunctions. Moreover, the co-exposure of discrete cocatalyst and semiconductor increases the product diversity when both the exposed sites of which participate in CO 2 photoreduction. Herein, we present a facile and versatile protocol to overcome these limitations via surface coating of Z-scheme heterojunctions with bifunctional noble-metal-free cocatalysts. With Cu 2 O/Fe 2 O 3 (CF) as a model heterojunction and layered Ni(OH) 2 as a model cocatalyst, it is found that Ni(OH) 2 lying on the surfaces of Cu 2 O and Fe 2 O 3 separately co-catalyzes the CO 2 reduction and H 2 O oxidation. Thorough experimental and theoretical investigation reveals that the Ni(OH) 2 outer layer: (i) mitigates the charge recombination in CF and balances their transfer and consumption; (ii) reduces the rate-determining barriers for CO 2 -to-CO and H 2 O-to-O 2 conversion, (iii) suppresses the side proton reduction occurring on CF, and (iv) protects the CF from component detachment. As expected, the redox reactions stoichiometrically proceed, and significantly enhanced photocatalytic activity, selectivity, and stability in CO generation are achieved by the stacked Cu 2 O/Fe 2 O 3 @Ni(OH) 2 in contrast to CF. This study demonstrates the significance of the synergy between bifunctional cocatalysts and Z-scheme heterojunctions for improving the efficacy of overall redox reactions, opening a fresh avenue for the rational design of artificial photosynthetic systems.

The experiment was conducted to evaluate the effects of cow manure compost (CMC) application on respiratory and enzyme activities of leachate-polluted soils. Soils treated with various levels of leachate (0, 12.5, 25, 37.5, and 50 ml leachate per 300 g soil) were amended with 0, 25 and 50 g CMC, respectively. Soil pH, respiration and enzyme activities were evaluated by regularly repeated sampling. Addition of CMC neutralized pH and maintained it within the range of 6.4–6.7 in a long run. Respiration was increased neither by leachate nor by CMC. This probably results from deterioration of soil compaction, biotoxicity of leachate, or increased fungi proportion. Enzyme activities increased with increasing CMC application but decoupled with leachate addition rate, reasonably attributed to pH neutralization and high content of humus in CMC. Thus, pH value and humus content could be considered as key items affecting soil enzyme activities.

In this study, we report on an active and stable CoMgAl layered double hydrotalcite (LDH) catalyst for phenol degradation by heterogeneous activation of peroxymonosulfate (PMS). The CoMgAl-LDH catalyst was synthesized by hydrothermal method. The PMS/CoMgAl-LDH system overcomes the drawbacks of traditional Fenton processes. Various effects, e.g., scavengers, chloride ion, catalyst dosage, PMS concentration, temperature, and pH, were also inspected to evaluate the system. The results indicated that the PMS/CoMgAl-LDH system had extremely high efficiency for phenol degradation; 0.1 mM phenol could be completely degraded by 0.3 g/L catalyst and 3 mM PMS within 60 min at 30 °C. The CoMgAl-LDH catalyst appeared to possess outstanding reusability and stability. After four rounds of recycling, nearly 100% of the phenol was removed within 80 min by the PMS/CoMgAl-LDH system, with only 0.05 mg/L Co2+ leaching. A sulfate radical was the main oxidation species in the PMS/Co-LDH system. The degradation rate of phenol was influenced by temperature, and the activation energy was 65.19 kJ/mol. These advantages proved the PMS/CoMgAl-LDH system is an effective strategy for the treatment of organic contaminants.

In past 15 years, haze has become one of the most concerned environmental problem in China. This study examines China’s performance on haze research using scientometrics indicators such as China’s global publication share, rank, growth rate and citation impact, its publications in various areas, top journals based on last 15 years (2000–2014) publications data obtained from ISI Science citation index expanded database. Chinese share with international collaborative papers, h-core papers and high-cited papers were also determined. The results indicated a constantly rise in the amount of published papers, the average citations per paper and the presence of Chinese researchers and institutions in top journals. However, the impact and quality of the papers were far to satisfactory. There was still a great gap for impact between China and developed countries (G7 countries) in haze research.

In situ degradation of organic contaminants by Pd and electro-generated H 2 and O 2 overcomes the drawbacks to traditional Fenton process, and conducting heterogeneous catalyst of FeMgAl layered double hydrotalcite (LDH) further improved the efficiency and stability. Using bisphenol A (BPA) as the model contaminants, 90% removal can be achieved with 1200 mg/L Pd/Al 2 O 3 and FeMgAl-2. The reusability was satisfying due to the very limited leaching of Fe ions at 0.1 ppm level. FeMgAl also amplified the window of pH for Pd-catalyzed in situ advanced oxidation processes (AOPs) from 3 by homogenous Fe(II) to 3–7 by FeMgAl LDH. The COD of landfill leachate effluent of the MBR system removed by about 52.3% by this system by the initial pH was 5. Characterizations revealed the distinguishing features associated with LDH structure such as large surface area, good stability, basic character, and strong linage among active sites were accounted for the remarkable performances over a wide pH window. Five reactive intermediates were observed and multiple degradation pathways were proposed in Pd-catalyzed in situ AOP for the first time. Interestingly, because of the unique role of Pd catalyst, these degradation pathways were clearly distinguished from traditional Fenton or Fenton-like AOPs and may provide a new approach of in situ heterogeneous AOPs for refractory contaminants in future.

Phenylurea herbicide residuals in soil may continuously contaminate surface water and groundwater due to unregulated and improper use. Herein, we reported a stable and active oxidation system including heterogeneous Fe-based layered double hydroxide materials as persulfate (PS) activators. Under mild conditions, 1% LDH in weight and 70 mM PS can completely degrade 500 mg/kg isoproturon in soil within 10 h, during which less than 0.1 ppm heavy metal leaching was detected. This remarkable performance was consistent in a broad pH range (3~11) and was resistant to various inorganic anions (Cl − , Br − , NO 3 − , HCO 3 − ) and humic acid. Mechanism studies from scavenging tests, EPR, and fluorescence spectra collectively proved that besides •OH and •SO 4 − , singlet oxygen ( 1 O 2 ) and superoxide (•O 2 − ) were also generated and were accounted for the oxidative degradation. This unique mechanism of generating diverse radicals was clearly distinguished from classic Fe(II)/PS system, significantly reduced the influence of varying parameters in water and soil matrix, and was suggestive to chemical oxidation system in soil remediation to avoid scavenging effects by background electrolytes or other components in water/soil matrix. Graphical abstract ᅟ

In this paper, a new type of carbazole-based hyper-crosslinked porous polymer (HCP-CP) was prepared through a very simple “knitted” method. The obtained novel polymer HCP-CP has a good adsorption property of methyl orange (MO) and methylene blue (MB) organic dyes in aqueous solution due to its high surface area and rich nitrogen atoms. The effect of pH, adsorption time, different initial concentration of dyes and adsorption reusability were investigated in detailed. The optimum pH is 8 for the adsorption of MB and 6 for the adsorption of MO, respectively. Under the best condition, the Langmuir model fitted the adsorption isotherm well and the adsorption behavior follow pseudo-second-order kinetics. The maximum adsorption capacity of HCP-CP for cationic dye MB (q max =751.88 mg/g) is more than twice higher than that of anionic dye MO (q max =274.73 mg/g). These capacity differences may be owing to the stronger electrostatic interaction between the negatively charged nitrogen atoms of HCP-CP with the cationic dye MB than that of MO. Moreover, the used polymer HCP-CP still retain a removal percentage above 92% after 5 times adsorption-desorption recycle. Therefore, this work provided a convenient synthetic route to develop a novel hyper-crosslinked polymer with high adsorption capacity for the entrapment of dyes from aqueous solution.

In this work, we designed and synthesized two novel bi-heteroatom functionalized hyper-crosslinked porous polymers (HCP-CT and HCP-CF) through a simple one-step Friedel–Crafts alkylation reaction. The resulted polymers N/S bi-heteroatom functionalized polymer HCP-CT and N/O bi-heteroatom functionalized polymer HCP-CF both have good adsorption property for organic dyes such as methyl orange (MO) and methylene blue (MB) in aqueous solution due to its rich pore structure, high specific surface area and rich-heteroatoms of pore surface. It is worth mentioned that the maximum adsorption capacity ( q max ) of cationic dye MB by the porous polymer HCP-CT at room temperature was reached up to 1571.46 mg/g, which is much higher than that of most reported porous materials. Furthermore, the adsorption capacity of HCP-CT for the cationic dye MB was more than seven times that of the anionic dye MO ( q max  = 212.77 mg/g). Also, the polymer HCP-CF for the MB adsorption capacity ( q max  = 352.11 mg/g) was more than twice higher than that of anionic dye MO ( q max  = 131.75 mg/g). The above trends may be because of the stronger electrostatic interaction between the negatively charged N-S/O bi-heteroatom of HCP-CT and HCP-CF with the cationic dye MB than that of MO. In addition, the removal percentage of polymers HCP-CT and HCP-CF still remained above 80% after five adsorption–desorption cycles. Hence, this work may provide a convenient synthetic route to develop a novel hyper-crosslinked polymer with high capacity for the entrapment of dyes from aqueous solution.