Search

Considering the biocompatibility of natural proteins and the strong photo-redox capability of Z-scheme heterojunctions, we fabricated Z-scheme ZnIn

Novel p–n heterojunction of Cu2O/Bi2O2CO3 photocatalysts with various proportion of Cu2O are synthesized by the precipitation method at room temperature, which are then combined with electrospinning method and electron beam irradiation to construct a photocatalyst-polymer structure. The results indicated that the Cu2O/Bi2O2CO3 photocatalyst obtained, in contrast to the pure Bi2O2CO3, enabled improved visible-light absorption, which can separate and migrate the charge carriers efficiently via solid p–n heterojunction interfacial effect. Accordingly, the Cu2O/Bi2O2CO3/PEO nanofibers allowed for the higher visible-light-responsive photocatalytic activity for the degradation of chloramphenicol (CAP), which the highest degradation efficiency is 98.2% for CAP in 30 min and obviously higher than that of Bi2O2CO3 membrane. In addition, combining cytotoxicity experiments with LC-IT-QTOF, it is found that intermediates such as DH-CAP and NO-CAP produced during the degradation of CAP are main possible reasons for the increase in the solution cytotoxicity. Besides, the obtained materials show significant inhibition against Escherichia coli and Staphylococcus aureus with the maximum inhibition rates of 81.5% and 75.6%, respectively.

Polylactic acid (PLA) has been extensively applied in the fields of biology and renewable biodegradable materials because of its superior biodegradability. PLA has excellent potential as a renewable biodegradable adsorbent in wastewater treatment. However, its poor photocatalytic properties have hindered its practical application. In this study, polyvinylpyrrolidone (PVPP) or glutaraldehyde (GA) was utilized as an adhesive agent to prepare Ag/AgCl/PLA photocatalysts with highly efficient visible light photocatalysis on a PLA fabric by utilizing the electron beam irradiation method. The photocatalytic activities of the Ag/AgCl/PLA samples were examined under visible light irradiation to analyze the degradation of methylene blue (MB) and chloramphenicol (CPL). Our experimental results demonstrate that the nanomaterial Ag/AgCl was uniformly distributed on the PLA fiber surface; this can be attributed to the effects of the crosslinking PVPP or GA. Under electron beam irradiation, adding crosslinking PVPP (or GA) is beneficial to the loading of Ag/AgCl onto the PLA. For the composite Ag/AgCl/PLA, the degradation rate for MB was as high as 97% after 150 min of visible light irradiation. The addition of 4 mg/ml of Ag/AgCl solution resulted in the greatest photocatalytic activity for CPL, and we advanced the possible degradation pathways of CPL with the best sample. Additionally, the as-prepared composite Ag/AgCl/PLA exhibited favorable antibacterial activity against E. coli and S. aureus, with a bacterial removal rate of > 77%.

Due to its significant biocompatibility and environmental friendliness, the composite of heterojunction photocatalyst and natural protein is a promising material in the field of photocatalysis. For the first time, direct Z-scheme Bi2MoO6/Ag3PO4 composites with different concentrations of Ag3PO4 were successfully fabricated by an in-situ deposition method, and Bi2MoO6/Ag3PO4@silk fibroin (BMO/APO@SF) films were further constructed by electrospinning technology to explore the photocatalytic activity of heterojunction photocatalysts. The results of various characterizations confirmed that improved photocatalytic performance, including efficient charge separation, and a widened visible light absorption range, could be attributed to the formation of a heterojunction structure between Bi2MoO6 and Ag3PO4, which considerably promoted photocatalytic activity for ciprofloxacin (CIP) degradation. According to the analysis of degradation products measured by Q-TOF, possible CIP degradation pathways were proposed. Density functional theory (DFT) calculation and Laplacian bond order (LBO) analysis were consistent with the results of Q-TOF. Through trapping experiments, the significant contribution of O2– to BMO/APO@SF was demonstrated. Moreover, the antibacterial rates of Bi2MoO6/15Ag3PO4@SF (BMO/15APO@SF) against Escherichia coli and Staphylococcus aureus were greater than 94.36% and 95.72%, respectively, indicating that BMO/15APO@SF had excellent antibacterial performance.

Z-scheme heterojunction nanofibers are an efficient photocatalyst in water pollution control due to their strong photoredox properties and high separation efficiency. In this study, a highly efficient visible light-driven Z-type CeO2/Ag-AgVO3@zein photocatalytic fiber was synthesized by in-situ co-precipitation and electrospinning. CeO2/Ag-AgVO3@zein with cubic nodular fibers was composed of zein-coated CeO2/Ag-AgVO3 with a clavate spine structure. The composite photocatalysts exhibited improved visible-light photocatalytic activity over ultrafine CeO2 in the degradation of enrofloxacin pollutants. Through electrochemical tests and the optical properties of as-prepared photocatalysts, the enhanced photocatalytic activity could be attributed to formation of the Z-scheme photocatalytic system. CeO2/Ag-AgVO3@zein also displayed excellent disinfectant and antibacterial efficacy of over 80% against Gram-positive/Gram-negative bacteria, resulting from the actions of CeO2/Ag-AgVO3-triggered ROS. Besides, the results of in-vitro and in-vivo experiments showed that CeO2/Ag-AgVO3@zein had good cytocompatibility. Accordingly, CeO2/Ag-AgVO3@zein has been identified as a promising photocatalyst for treatment of pharmaceutical industry wastewater.

In this study, the Bi2O2CO3-Cu2O composite has been fabricated via a facile in-situ coprecipitation way and then a novel photocatalytic film SF/Bi2O2CO3-Cu2O has been first prepared by electrospinning. The as-prepared materials were characterized by XRD, XPS, SEM, TEM, FTIR and UV–vis, etc. technologies. The formation of Bi2O2CO3-Cu2O heterostructure was conducive to the separation and transport of carriers, and thus enhancing visible-light-driven photocatalytic property. Accordingly, the highest photodegradation efficiency of SF/Bi2O2CO3-Cu2O for chloramphenicol achieved 98.3% in 30 min, which was much higher than that of SF/Bi2O2CO3. Concurrently, the SF/Bi2O2CO3-Cu2O nanofiber can easily separate from the water due to its self-supporting structure provided by electrospinning silk fibroin. According to the photodegradation mechanism and the analysis of degradation products measured by Q-TOF, we also proposed the possible degradation pathways of chloramphenicol. It was found that the S. aureus and E. coli growth suppressed by 71.09% and 80.63% respectively after SF/Bi2O2CO3-Cu2O treatment. Finally, we have proved the low-cytotoxicity of the membrane through the Cell Counting Kit-8 method.

The limitations of the existing means of treating brewers' spent grain and sewage sludge highlight the need to find sustainable routes to manage them. Biochars derived from their mixtures enriching with magnesium and phosphorus, through pyrolysis at 400–700 °C, were characterized, and their potential use as a capture agent for ammonia-nitrogen removal in aqueous solutions was also analyzed. The yield increased with rising brewers' spent grain ratio, but decreased with increasing temperature. Higher pyrolysis temperature caused higher ash content, pH, surface basicity, specific surface area, and mineral element concentrations, whereas lower surface acidity, cation exchange capacity and nitrogen contents. Biochars derived from the mixtures of brewers' spent grain and sewage sludge (80:20, wt%) gained the highest removal efficiencies of ammonia-nitrogen, owing to their high surface area, magnesium and phosphorus availability, suitable surface chemistry and morphology. Compared with other biochars for ammonia-nitrogen adsorption, the biocahrs had high removal efficiencies (above 60%), which also had the potential to sustainably contribute to carbon dioxide emission reduction and nitrogen recovery.

Lime mud from papermaking process (LMP) is a solid waste originated from the causticization process. Due to fine particle size and high alkalinity of LMP, its recovery is expensive and adverse effect is still uncertain. This review presents several current techniques proposed for LMP utilization in order to minimize its toxic effect on the environment. Conventional uses such as soil amendments, landfill and building materials are continually conducted. Recently, novel utilization of LMP to immobilize and remove pollutants in different phases (liquid, solid and gas) has provided new opportunities for efficient removal of dye, organics, heavy metals, carbon dioxide and sulfur dioxide. Moreover, as an additive summarized in this review, LMP can enhance the performance of biological process for treating organic waste, and its available value would be potentially improved further.

Designing for indoor thermal environmental conditions is one of the key elements in the energy efficient building design process. This paper introduces a development of the Chinese national Evaluation Standard for indoor thermal environments (Evaluation Standard). International standards including the ASHRAE55, ISO7730, DIN EN, and CIBSE Guide-A have been reviewed and referenced for the development of the Evaluation Standard. In addition, over 28,000 subjects participated in the field study from different climate zones in China and over 500 subjects have been involved in laboratory studies. The research findings reveal that there is a need to update the Chinese thermal comfort standard based on local climates and people's habitats. This paper introduces in detail the requirements for the thermal environment for heated and cooled buildings and free-running buildings in China.

The effects of lime mud from papermaking process (LMP) addition as buffer agent and inorganic nutrient on the anaerobic digestion stability of food waste (FW) were investigated under mesophilic conditions with the aim of avoiding volatile fatty acids accumulation, and inorganic elements deficiency. When LMP concentration ranged from 6.0 to 10g/L, the FW anaerobic digestion could maintain efficient and stable state. These advantages are attributed to the existence of Ca, Na, Mg, K, Fe, and alkaline substances that favor the methanogenic process. The highest CH4 yield of 272.8mL/g-VS was obtained at LMP and VS concentrations of 10.0 and 19.8g/L, respectively, with the corresponding lag-phase time of 3.84d and final pH of 8.4. The methanogens from residue digestates mainly consisted of Methanobrevibacter, coccus-type and sarcina-type methanogens with LMP addition compared to Methanobacteria in control. However, higher concentration of LMP inhibited methanogenic activities and methane production.

Hydrogen production via anaerobic fermentation may suffer from instability or inhibition due to volatile fatty acids concentrations and inorganic elements deviations from optimality. A slight addition of white mud from ammonia–soda process (WMA) to the fermentation may show a feasible implement approach to use as buffer and inorganic nutrient. Batch tests were conducted to study the effect of the WMA addition on the hydrogen fermentation of food waste (FW) for the purpose of the maximum hydrogen yield (MHY) while achieving process stability and microbial germination through the endogenous alkalinity and inorganic elements of WMA. This was attributed to the existence of calcium, sodium, magnesium, potassium and alkali-rich materials, like calcium carbonate. 3 g of WMA addition to 200 g FW and fermentation time of 36 h resulted in obtaining the MHY of 145.4 mL H2/g VS, with a corresponding lag-phase time of 3.0 h. Under these operating conditions, the fermentation process demonstrated one of the highest measured stability with final pH 5.3.

The effect of lime mud from paper-making process (LMP) addition on the H2 fermentation of food waste (FW) was investigated. It was found that a slight addition of LMP (1.0–4.0 g in 200 g FW) significantly enhanced the H2 fermentation performance, not only increasing the total amount of H2 produced but also accelerating the whole reaction, shortening the lag period, and increasing the H2 production rate. Fermentation stability and microbial germination were also facilitated by LMP addition. This was attributed to the existence of Ca, Fe, Mn and alkaline substances such as CaCO3 and NaOH. The batch process treating a mixture of FW and LMP was showed that the highest hydrogen production of 137.6 mL H2/g VS was achieved at final pH 5.0, adding 3 g LMP (in 200 g FW) to the fermentation process, which lag-phase time was about 2.5 h.