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In this paper, CdS nanorings synthesized by a facile hydrazine-induced microwave method for the photodegradation of pollutants were reported for the first time. Different reaction method, microwave power, the category and dosage of pH regulating reagent, reaction temperature and reaction time were investigated. The formation of CdS nanorings from the self-assembly of nanoparticles was attributed to the coordination of hydrazine producing the dipole–dipole interaction among the uniform nanoparticles prepared by microwave method. The crystal phase, composition, morphology and surface property of CdS nanorings were characterized. The results showed that 100 nm-sized wurtzite CdS nanorings generated with the self-assembly of 5–8 nm nanoparticles, which presented mesoporous structures. To study the influence of ring-like structures on the photocatalysis, the photodegradation of rhodamine B (RhB) with CdS nanorings and nanoparticles was compared. The results showed that, CdS nanorings displayed higher photodegradation efficiency, which were originated from more favorable band edge potential and effective electron–hole separation producing more superoxide radical and holes as active specifies. The photodegradation path of RhB contained the process of the demethylation, the decarboxylation process, the chromophore cleavage and ring-open reactions. Finally, the available photodegradation of multiple pollutants and reusability of CdS nanorings were carried out. [ABSTRACT FROM AUTHOR]

In this paper, two morphologies of crystalline Sb2S3 as dumbbell-like Sb2S3 and bundle-like Sb2S3 were synthesized by different phase-transformation of amorphous-to-crystalline, respectively. Different factors such as the variation of the solvent ratio, the surfactant, reaction temperature and reaction time were observed to obtain the key factor influencing the morphology. The bandgap of two Sb2S3 was obtained by diffused reflectance spectra and cyclic voltammetry. The charge separation was characterized by fluorescence spectrum, linear sweep voltammetry, transient photocurrent-time curve and electrochemical impedance spectrum. The results showed that bundle-like Sb2S3 had slightly higher light-harvesting and obvious higher charge separation ability, which was beneficial to the photodegradation of malachite green (MG). The photodegrdation path of MG implied the intermediates generated by bundle-like Sb2S3 were more easily decomposed to the small molecules. Bundle-like Sb2S3 displayed excellent reusability in the photodegradation of MG. Superoxide anion radical (·O2−) and hydroxyl radical (·OH) as the active species contributed to the photodegradation reaction. [ABSTRACT FROM AUTHOR]

Two morphologies of In 2 S 3 film were synthesized directly on FTO surface with microwave-assistant solution method. With reaction time/temperature/microwave power increasing, In 2 S 3 film assembled by hierarchical flower-like structure (In 2 S 3 flower) transformed into In 2 S 3 film assembled by net-like structure (In 2 S 3 net) with increased size and crystallinity. Compared to In 2 S 3 flower, In 2 S 3 net displayed stronger light-harvesting ability with higher charge separation, contributing to stronger photocurrent and lower charge transfer resistance. Based on the excellent photoelectrical properties, TiO 2 /In 2 S 3 /CuInS 2 /spiro-oMeTAD solar cells were fabricated with two In 2 S 3 films as the buffer layers as compared to the device without In 2 S 3 , which displayed obviously higher photovoltaic parameters due to the decreased surface defects on TiO 2 and the increased complementary absorption from In 2 S 3. Furthermore, the device with In 2 S 3 net presented higher short current density (J sc) than that with In 2 S 3 flower because the thicker In 2 S 3 layer strengthened the contribution of complementary light-harvesting. However, it displayed lower open circuit voltage (V oc), which was attributed to the presence of defects on the surface of overgrown In 2 S 3 for increased interfacial recombination. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have shown great prospects in wastewater remediation. However, the easy aggregation, difficult separation and inferior reusability greatly limit their large-scale application. Herein, we proposed a facile, green and low-cost strategy to construct robust and stable MOF-based hydrogel beads (Fe-BTC-HBs) in a gram scale, and employed them to remove antibiotics from wastewater. As a result, the Fe-BTC-HBs demonstrated outstanding adsorption capacity for both ofloxacin (OFL) and tetracycline (TC) (281.17 mg/g for OFL and 223.60 mg/g for TC) under a near-neutral environment. The main adsorption mechanisms of OFL and TC were hydrogen bonding and π ‐ π stacking interaction. Owing to its macroscopic granule and stable structure, Fe-BTC-HBs can be separated rapidly from wastewater after capturing antibiotics, and more than 85% adsorption capacity still remained after six cycles, while the powdered Fe-BTC only showed less than 6% recovery efficiency with massive weight loss (around 92%). In real industrial effluent, the adsorption performance of Fe-BTC-HBs toward two antibiotics exhibited negligible decreases (2.9% for OFL and 2.2% for TC) compared with that in corresponding solutions. Furthermore, Fe-BTC-HBs also had appealing economic and environmental benefit. Overall, the macro-manufactured MOF beads have the promising potential for the large-scale wastewater treatment. [Display omitted] • A facile, green and low-cost strategy was proposed to construct robust and stable MOF beads. • The macro-manufactured MOF hydrogel beads had outstanding adsorption capacity for antibiotics. • High anti-interference capability was shown on antibiotic adsorption in industrial effluent. • Excellent reusability, economic and environmental benefit promoted MOF materials to application. [ABSTRACT FROM AUTHOR]

[Display omitted] • In 2 O 3 film is used as an electron transport layer in Perovskite Solar Cells. • The In 2 O 3 electron transport layer is prepared by electron beam evaporation. • In 2 O 3 layer can improve the film formation quality and crystallinity of perovskite. • The photovoltaic performance of perovskite solar cells is enhanced by In 2 O 3 layer. In perovskite solar cells, the interface plays a crucial role in photovoltaic performance because excitons dissociate and compound at the interface. In this paper, the optical absorption layer of In 2 O 3 planar perovskite solar cells is studied, which is an efficient intermediate layer between the TiO 2 electron transport layer and perovskite. The modification of the In 2 O 3 interlayer increases the average power conversion efficiency from 6.74% to 10.68%. Based on this background, some other feature descriptions are also carried out. The results show that the photovoltaic performance can be improved by depositing the In 2 O 3 interlayer, mainly due to the improved film morphology, reduced recombination center, bulk carrier concentration and Hall mobility. It has been shown that In 2 O 3 can be used as an efficient interface material on all-inorganic perovskite solar cells. [ABSTRACT FROM AUTHOR]

Red mud was modified by impregnation with Co element loading. The Co-RM catalyst was characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray fluorescence (XRF), and UV full-band scanning. The results showed that the modified Co-RM catalyst successfully loaded the Co element and formed an irregular pore structure on the surface, thereby increasing the number of active sites of the red mud catalyst and effectively improving the degradation efficiency of tetracycline. Under the optimal conditions of a catalyst dosage of 0.3 g/L, a persulfate dosage of 3 g/L, a reaction temperature of 50 °C, and a pH value of 7, a removal rate of 50 mg/L of tetracycline can be achieved: 89.5% after 90 min. The effects of common anions and humic acids in water, as well as radical quenchers (anhydrous ethanol and tert-butanol), on the degradation of tetracycline were investigated. The results showed that Cl−, CO32−, HCO3−, H2PO4−, NO32−, HPO42−, and humic acids showed inhibitory effects on the degradation of tetracycline, while SO42− showed a promoting effect on the degradation of tetracycline. The free radical quenching experiment showed that the most important free radicals that can degrade tetracycline in the system are sulfate radicals. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel cationic polymer modified magnetic adsorbents (MCDs) were fabricated. • MCDs have huge "force field" owing to strong electrostatic attraction. • MCDs have a high adsorption capacity for food dyes Food Yellow 3 and Acid Yellow 23. • The adsorption capacity decreases slightly with pH changing from 2.0 to 10.0. • Multiple adsorption mechanisms are involved in the food dye adsorption. Abstract In this study, modified magnetic chitosan microparticles (MCDs) were fabricated and used as adsorbents for the removal of Food Yellow 3 (FY3) and Acid Yellow 23 (AY23) from aqueous solution. The magnetic microparticles were characterized by scanning electronic microscope, Brunauer-Emmett-Teller specific surface area, elemental analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetry analysis, differential scanning calorimetry, and vibrating-sample magnetometer. Then, the effects of pH value, initial dye concentration, and contact time on the adsorption of FY3 and AY23 by MCDs were investigated. Evidently, MCDs showed excellent adsorption performance for both food dyes, and their adsorption capacities (833.33 mg/g for FY3 and 666.67 mg/g for AY23) were considerably higher than those of unmodified adsorbents, which could be attributed to the electrostatic interaction and ion exchange between the grafted cationic polymer and food dyes. Adsorption isotherm and kinetic data of the magnetic microparticles were well fitted by Langmuir isotherm and pseudo-second-order kinetic model, respectively. The regeneration and reusability of MCDs were also explored. Results showed that more than 80% adsorption capacities of MCDs for FY3 and AY23 remained after five adsorption-desorption cycles. [ABSTRACT FROM AUTHOR]

Novel adsorbents, poly([2-(methacryloxy)ethyl]trimethylammonium chloride) modified magnetic chitosan particles (DMCPs), were synthesized via free radical polymerization and applied to adsorb Cr(VI) from aqueous solution. The effects of pH (2–11), Cr(VI) concentration (10–200 mg/L) and contact time (0–420 min) on the adsorption performance were evaluated. The results showed that the adsorption capacity of DMCPs was much larger than that of magnetic chitosan particles (MCPs) in the examined pH range and decreased with Cl − concentration increasing, indicating that electrostatic interaction and ion exchange are the governing mechanisms of Cr(VI) adsorption by DMCPs. The Langmuir isotherm model and pseudo-second-order kinetic model fitted the experimental data well. The maximum adsorption capacity of DMCPs is 153.85 mg/g. Besides, Cr(VI)-loaded DMCPs could be easily separated and efficiently regenerated. Therefore, DMCPs are promising candidates for Cr(VI) adsorption owing to their excellent performance in a wide pH range, easy separation and good reusability. [ABSTRACT FROM AUTHOR]

Layered design is an important method for improving the loss factor of damping materials. However, the composite loss factor does not increase with the increase of the number of layers of the damping material. In response to this issue, this paper investigates the mechanism by combining experimental and simulation analyses. First, for the damping material itself, the relationship between the material loss factor and the number of damping layers was studied based on dynamic mechanical analysis. Second, for the composite structure of damping material and substrate, the relationship between the composite loss factor and the number of damping layers of the free damping structure was obtained by the cantilever resonance method, and the influence of material and structure parameters on the composite loss factor was clarified by finite element analysis. Finally, for aiming at the composite structure of damping material with constraint layer and substrate, the mechanism of the influence of the number of layers of layered damping material on the uncertainty of the composite loss factor was further investigated and discussed. The results indicated that for free damping structures, the composite loss factor increases with the increase of the number of damping layers only when the elastic modulus of the damping layer is similar to that of the substrate. For constrained damping structures, only when the constraint layer is relatively thin and has a certain amount of density and modulus, the composite loss factor of the constrained damping structure increases as the number of damping layers increases. Highlights: The mechanism by which the number of layers of damping material affects the composite loss factor has been clarified.The composite loss factor does not necessarily increase as the number of layers of damping material increases.The composite loss factor of a free damping structure is mainly influenced by the Young's modulus of the damping layer.The composite loss factor of constrained damping structures is mainly influenced by the thickness, density, and modulus of the constrained layer. [ABSTRACT FROM AUTHOR]

• A magnetically separable amphoteric biosorbent (PD-Fe 3 O 4 @CCS) was fabricated. • The PD-Fe 3 O 4 @CCS displayed effective adsorption performance for Cr(VI) and Cu(II). • Adsorption behaviors of Cr(VI) and Cu(II) in single and binary systems were studied. • Ion exchange, electrostatic and coordination (chelation) interactions are involved in Cr(VI) (Cu(II)) adsorption. Here we unveiled a novel magnetically separable amphoteric biosorbent (PD-Fe 3 O 4 @CCS) and investigated its adsorption behavior toward two classes of heavy metals, hexavalent chromium (Cr(VI)) and copper (Cu(II)) ions from water. Results indicated that the adsorption behavior of PD-Fe 3 O 4 @CCS for Cr(VI) was well described by Langmuir model; while for Cu(II) adsorption, the Freundlich model was the better one. Based on the kinetic results, both Cr(VI) and Cu(II) adsorption on PD-Fe 3 O 4 @CCS fitted well with the pseudo-second-order kinetic model. To evaluate the reusability and stability of PD-Fe 3 O 4 @CCS, regeneration tests were carried out for five cycles. Furthermore, the applicable feasibility of PD-Fe 3 O 4 @CCS in the real water matrix (including the single and binary pollutant systems) was studied, and results suggested the promising potential of PD-Fe 3 O 4 @CCS for large-scale application. Apart from these, the surface interactions between PD-Fe 3 O 4 @CCS and heavy metal ions in single and binary systems were systematically investigated based on FTIR and XPS analyses, which provided an essential implication for comprehending the interactions between biosorbents and contaminants in wastewater. [ABSTRACT FROM AUTHOR]

• Magnetic biosorbents (PMCCs) were designed and fabricated by radical polymerization. • PMCCs had specific morphological and molecular structure for ciprofloxacin removal. • PMCCs exhibited excellent adsorption capacity of 527.93 mg·g−1 for ciprofloxacin. • The adsorption mechanisms of ciprofloxacin by PMCCs were systematically elucidated. • PMCCs displayed rapid separation and favorable reusability. Magnetic biosorbents with specific morphological and molecular structure (PMCCs) were designed for the removal of ciprofloxacin (CIP) from water. Radical polymerization method was applied to immobilize the designed polymer brushes onto core-shell shaped magnetic microspheres to fabricate PMCCs. PMCCs exhibited a maximum adsorption capacity of 527.93 mg·g−1, which is much higher than reported adsorbents, owing to the complete stretch of polymer brushes and increased active sites as well as enhanced interaction. The investigation on the adsorption behavior of PMCCs for CIP manifested that CIP adsorption well fitted the Langmuir isotherm model and pseudo-second-order kinetic model. The calculated thermodynamic parameters suggested that CIP adsorption onto PMCCs was spontaneous and exothermic. Further recycling experiments showed a loss of less than 20% in the CIP adsorption capacity after five times, demonstrating the reusability of the as-designed biosorbents. [ABSTRACT FROM AUTHOR]

• A novel surface-decorated magnetic chitosan biopolymer (VMCP) was fabricated. • VMCP exhibited significantly improved removal performance toward Cr(VI). • Simultaneous adsorption and reduction of VMCP for Cr(VI) was investigated. • The mechanisms of Cr(VI) removal by VMCP were elucidated. Poly(4-vinyl pyridine) decorated magnetic chitosan biopolymer (VMCP), as an absorbent and reductant, was prepared and used to remove hexavalent chromium (Cr(VI)) from aqueous solution. Compared with undecorated magnetic biopolymer, VMCP exhibited significantly improved removal performance under identical experimental conditions. The kinetics, isotherms, and thermodynamics of Cr(VI) adsorption onto VMCP were investigated. Results demonstrated that the maximum monolayer adsorption capacity of VMCP was 344.83 mg/g, which was considerably higher than most reported adsorbents. The mechanism for Cr(VI) removal was explored based on XPS and FTIR analyses. The main mechanisms were concluded to be Cr(VI) adsorption onto the positively charged VMCP surface and the reduction of Cr(VI) to Cr(III), followed by coordination between Cr(III) and N atoms. The easy regeneration, satisfactory reusability, and remarkable performance in column tests revealed the high potential of VMCP in treating Cr(VI)-contaminated water. [ABSTRACT FROM AUTHOR]

Metal-assisted chemical etching (MACE) method is an efficient way to improve the power conversion efficiency of solar cell by developing nanostructures. Normally, hydrogen peroxide is widely used as an oxidizing agent, through which anisotropic etching of nanostructures could be achieved. Here, nanoscale textured multi-crystalline silicon (mc-Si) solar cell with an efficiency of 18.13% was fabricated by MACE method with potassium permanganate (KMnO4) as an oxidizing agent. The isotropic etching by KMnO4 showed the great uniformity of surface reflectance, corresponding to the isotropic oval pits. The solar cell presented an increase of 0.72mA · cm−2 in the short-circuit current density comparing with the mc-Si solar cell fabricated by the traditional process. Though the efficiency still needed optimizing, isotropic etching for mc-Si would lead a new tendency for MACE technique. [ABSTRACT FROM AUTHOR]

The absence of an effective texturing technique for diamond-wire sawn multi-crystalline silicon (DWS mc-Si) solar cells has hindered commercial upgrading from traditional multi-wire slurry sawn silicon (MWSS mc-Si) solar cells. In this work, we present a novel method for the removal of diamond-wire-sawn marks in a multi-crystalline silicon wafer based on metal assisted chemical etching process with Cu/Ag dual elements and nano-structure rebuilding (NSR) treatment to make a uniform inverted pyramid textured structure. The temperature effect of NSR solution was systematically analyzed. It was found that the size of the inverted pyramid structure and the reflectance became larger with the increase of the NSR treatment temperature. Furthermore, the prepared unique inverted pyramid structure not only benefited light trapping, but also effectively removed the saw-marks of the wafer at the same time. The highest efficiency of 19.77% was obtained in solar cells with an inverted pyramid structure (edge length of 600 nm) fabricated by NSR treatment at 50 °C for 360 s, while its average reflectance was 16.50% at a 400–900 nm wavelength range. [ABSTRACT FROM AUTHOR]

In this paper, a simple and cost-effective wet chemical method is presented to form quasi-inverted pyramids (QIP) on ultrathin c -Si for efficient light trapping and sufficient wettability. The QIP is fabricated by a well-known two-step Ag assisted chemical etching method followed by a post nanostructure rebuilding (NSR) process. The variation of [Ag + ] realizes the modulation of QIP size from sub-micro scale to micro scale. The comparable average absorptance value of 50 µm c -Si with double-sided QIP fabricated under 0.5 mM [Ag + ] (QIP-50) to that of 182 µm c -Si with double-sided conventional micro-scale pyramid in the spectral range of 300 – 1100 nm demonstrates an over 3.6-fold reduction in material usage. In comparison with nanopores-structured light-trapping configuration, the QIP-50 possesses much smaller specific surface area of ~2.39, which alleviates the surface recombination losses. After wet oxidation treatment, the water contact angle (WCA) of QIP-50 (35.73°) can achieve a comparable value to that of wet oxidized polished wafer (33.30°), demonstrating sufficient wettability of the QIP for high efficiency ultrathin c -Si/PEDOT:PSS hybrid solar cells. The finding of QIP with both efficient light trapping and superior wettability provides a new opportunity to improve the performance of ultrathin c -Si/PEDOT:PSS hybrid solar cells with a simple process at low cost. [ABSTRACT FROM AUTHOR]

In this paper, we report inverted pyramidal nanostructure based multi-crystalline silicon (mc-Si) solar cells with a high conversion efficiency of 18.62% in large size of 156 × 156 mm 2 wafers. The nanostructures were fabricated by metal assisted chemical etching process followed by a post nano structure rebuilding (NSR) solution treatment. With increasing NSR treatment time, the reflectance and the dimensions of micro oval pits were both influenced. Resulting from both the light trapping ability and passivation efficiency, 500 nm inverted pyramid structure exhibited an ideal solar cell performance. The best solar cell showed a low reflectivity of 3.29% and a 0.91 mA cm −2 increase of short-circuit current density, and its efficiency was 0.45% higher than the acid textured solar cell. This technique presented a great potential to be a standard process for producing highly efficient mc-Si solar cells in the future. [ABSTRACT FROM AUTHOR]

In this paper, flexible, robustly adhesive, surface smooth and oxide-resistive AgNWs/AZO composite transparent conductive films (TCFs) were prepared by spin-coating solvothermal derived AgNWs followed by magnetron sputtering AZO protective layer, after which, annealing treatment at 200 ℃ for 20 min was adopted to further increase the performance of the composite film. The samples were characterized by means of X-ray diffraction, Raman spectroscopy, scan electron microscopy, scanning probe microscope, UV–Vis spectrophotometer and four point probe. The best result of AgNWs/AZO composite films was the one with a transmittance of 85% at 550 nm accompanied with a low sheet resistance of 19 Ω/□ by controlling the spin-coating times fixed at three. The figure of merit for the composite TCFs was 10.4, which was larger than the value of 8.8 for commercial ITO film. These amazing results would render the AgNWs /AZO composite TCFs an ideal candidate to replace conventional ITO for its potential application in flexible devices including OPV and OLED. [ABSTRACT FROM AUTHOR]

Acid texture is difficult for diamond wire sawn (DWS) multicrystalline silicon (mc-Si) wafer owing to the inhomogeneous distribution of damage layer on the surface. In this article, metal-assisted chemical etching (MACE) has been selected for introducing a porous seeding layer to induce acid texturing etching. SEM results show that the oval pit structures coverage get obvious improvement even on the smooth areas. Owing to the further improved light absorption ability by second MACE and nanostructure rebuilding (NSR) process, nanostructured DWS mc-Si solar cell has exhibited a conversion efficiency of 17.96%, which is 0.45% higher than that of DWS wafer with simple acid texture process. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

In this paper, Cu 2 ZnSnS 4 (CZTS)/reduced graphene oxide (RGO) composite was obtained by a hydrothermal treatment of the mixture of CZTS and graphene oxide (GO). The samples were characterized by means of X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and scan electron microscopy, thermal gravimetric analysis, and Brunauer–Emmmett–Teller (BET) test. The electrochemical performance of CZTS particles and CZTS/RGO composite used as supercapacitor electrodes was tested for the very first time. The electrochemical measurement demonstrated that the specific capacitance for CZTS/RGO in 3 M KOH aqueous electrolyte was as high as 591 F/g at a current density of 0.25 A/g which was four times larger than that of pure CZTS (138 F/g). Increasing the current density to 1 A/g, the specific capacitance of CZTS/RGO composite was kept as high as 248.5 F/g. After 1000 cycles, the capacity retention was still maintained at 80.6%. It was concluded that the high conductivity and large surface area of RGO resulted in the lower charge transfer and ion diffusion resistance in CZTS/RGO composite, which synergistically enhanced the capacitive performance of composite material. [ABSTRACT FROM AUTHOR]

• Multifunctional magnetic composite nanoparticles were facilely prepared. • The as-prepared FS@CS-PAA showed excellent adsorption capacities for cationic dyes. • FS@CS-PAA exhibited satisfactory removal rates for metal ions in a wide pH range. • The good adsorption ability was attributed to abundant active sites from CS-PAA. • FS@CS-PAA's good stability and reusability facilitated its practical application. Wastewater containing highly toxic, non-biodegradable and carcinogenic organic dyes and metal ions has been regarded as a severe threat to ecological environment and human health. Thus, it is of great significance to develop an effective approach to purify this kind of wastewater. Herein, novel magnetic adsorbent FS@CS-PAA was facilely prepared by coating anionic polyacrylamide-modified chitosan (CS-PAA) on the surface of silica-combined Fe 3 O 4 (FS). The morphology, structure, physic-chemical and magnetic properties of as-prepared FS@CS-PAA were fully characterized by various characterization techniques. Its adsorption behaviors towards cationic dyes and metal ions were systematically investigated in single systems, binary systems, and model wastewater. FS@CS-PAA was proved to have superior adsorption capacities of 2330.17 and 1044.06 mg g−1 respectively for crystal violet and methylene blue at 318.15 K, much higher than other reported adsorbents. Besides, FS@CS-PAA exhibited a pH-independent adsorption capability for metal ions, as demonstrated in single systems and in metal ion-dye binary systems, thus it could be used to treat a variety of metal ion wastewaters with different pH values. Moreover, FS@CS-PAA could be effectively and easily regenerated by HCl solution after the treatments of both synthetic wastewater and model wastewater. As revealed in FTIR and XPS analyses, the adsorption mechanism was mainly attributed to the electrostatic interaction, hydrogen bonding, cation exchange and chelating effect. With its excellent adsorption capacity for cationic dyes, pH-independent adsorption capability for metal ions, easy separation ability, satisfactory stability and good reusability, FS@CS-PAA can become an ideal candidate for wastewater treatment. [ABSTRACT FROM AUTHOR]

• The relationship between coagulation-flocculation and sterilization was emphasized. • Two flocculants played the different roles in drinking water treatment. • The synergistic effect of two coagulants for sterilization was confirmed by Contour Method. • Sterilization mechanism and kinetics of flocculants were revealed for the first time. • Sterilization was divided into two processes, rapidly adsorbing and slowly killing. In this study, the relationship between coagulation-flocculation and sterilization was studied using two conventional flocculants, polyaluminum chloride (PAC) and poly dimethyl diallyl ammonium chloride (PDMDAAC). Simulated wastewater containing kaolin and Escherichia coli was prepared. The bacterial removal rates of PAC and PDMDAAC under the same dosage are 46.3% and 19.5%, respectively. Which is far less than that of combined flocculants (94% bacterial removal rate). The synergistic effect of two flocculants was proved by contour method. β-Galactosidase activity, extracellular polysaccharides release, bacterial respiration activity and the activity of triphenyl tetrazolium chloride (TTC) dehydrogenase were investigated to clarify the sterilization kinetics and mechanisms. Two flocculants play the different roles in the treatment. PAC plays role of coagulation, charge neutralization, but PDMDAAC with quaternary ammonium groups is responsible for flocculation to form big flocs, which further enhances its contact with E. coli and contributes to sterilization. Sterilization by flocculants is divided into two processes, rapidly adsorbing and slowly killing, since the respiratory activity of E. coli in flocs gradually decreases with increasing contact time. The increase of flocculant dosage overcomes the hindrance of the secretion of extracellular polysaccharide polymers originating from E. coli to coagulation and sterilization. Sterilization of flocculant should be fully considered in drinking water treatment. [ABSTRACT FROM AUTHOR]

Though black silicon has excellent anti-reflectance property, its passivation is one of the main technical bottlenecks due to its large specific surface area. In this paper, multicrystalline black silicon is fabricated by metal assisted chemical etching, and is rebuilt in low concentration alkali solution. Different solution pre-treatment is followed to make surface modification on black silicon before Al2O3 passivation by atomic layer deposition. HNO3 and H2SO4 + H2O2 solution pre-treatment makes the silicon surface become hydrophilic, with contact angle decrease from 117.28° to about 30°. It is demonstrated that when the pre-treatment solution is nitric acid, formed ultrathin SiOx layer between Al2O3 layer and black silicon is found to increase effective carrier lifetime to 72.64 µs, which is obviously higher than that of the unpassivated black silicon. The passivation stacks of SiOx/Al2O3 are proved to be effective double layers for nanoscaled multicrystalline silicon surface. [ABSTRACT FROM AUTHOR]

In this paper, we report passivation properties of inverted pyramidal nanostructure based multi-crystalline silicon (mc-Si) by Al2O3 films with spin-coating method. Precursors AlCl3 and Al(acac)3 for Al2O3 films were chosen for comparison. Al2O3/SiOx stacks were found to be able to passivate the nanostructured surface well. With the number of spin-coating up to five, the Al2O3 films could conformally attach the nanostructure. The weighted average reflectance values (ranging from 400-900 nm) of the passivated silicon surface could be reduced to 10.74% (AlCl3) and 11.12% (Al(acac)3), and the effective carrier lifetime could reach 7.84 and 16.98 μs, respectively. This work presented a potential process to fabricate low cost high efficiency mc-Si solar cells. [ABSTRACT FROM AUTHOR]