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The introduction of dyeing sludge in the fired brick production is an economic and practical disposal approach. Wet dyeing sludge with high moisture usually produces block mass during mixing process of raw materials, not only reduces the production efficiency but negatively impacted products engineering properties. This study proposed a highly efficient method, wet sludge firstly being pelleted and then introduced in the production of fired bricks, to reduce the negative impacts on mixing process and the products quality. It was proved that the introduction of dyeing sludge pellets remarkably improved physical and mechanical properties of fired bricks. Especially, water absorption declined by 12% and compressive strength increased by 35% comparing with dyeing sludge without pelleting. The engineering properties of fired bricks containing 25 wt% sludge pellets are similar with that containing 15 wt% sludge without pelleting. The decrease in water absorption and porosity is mainly attributed to the reduction in number and volume of pores with diameter below 100 nm. It was considered that pellets with greater density and higher strength might play a role as aggregate to improve compressive strength. However, the introduction of sludge pellets with particle size over 8 mm is adverse to improving properties of products, because a large amount of macropore with diameter over 100 μm is produced, and destroys the homogeneous and compact structure of products. The optimal sludge pellet size is in the range of 2–6 mm based on products performance. The leaching toxicity of heavy metals from products is far lower than regulatory limitation. This study provides an advanced method to promote the disposal efficiency of solid waste and improve the engineering quality of products. • The introduction amount of dyeing sludge is promoted remarkably. • Physical and mechanical properties are improved significantly. • The optimal particle size of sludge pellets is 2–6 mm. • Pore volume below 100 nm in fired brick are reduced. [ABSTRACT FROM AUTHOR]

• A novel and high efficient approach to disposal of dyeing sludge is proposed. • Physical and mechanical properties are improved significantly. • The optimal particle size of sludge pellets is 2–6 mm. • The number and volume of pores below 100 nm are reduced due to pellets. The introduction of dyeing sludge in the production of fired brick is an economic and practical disposal approach. However, wet dyeing sludge is easy to form block mass during the mixing process of raw materials due to the high moisture content, which affected the production efficiency and destroyed the homogeneous structure of the fired brick, posing a negative impact on the engineering performance of the fired brick. In this study, wet sludge firstly is firstly pelleted and then introduced in the production of fired bricks to reduce the negative impacts on mixing process and the products quality. The results showed that the introduction of dyeing sludge pellets significantly improved the physical and mechanical properties of fired bricks. Compared with bricks incorporating dyeing sludge, water absorption is reduced by 24 % and compressive strength is increased by 101.6 %. The physical and mechanical properties of fired bricks incorporating 30 wt% of pelleting sludge are similar with bricks incorporating 20 wt% dyeing sludge without pelleting. The reduction in water absorption and porosity compared to that incorporating sludge without pelleting was mainly due to the reduction in the number and volume of pores of the same size. However, the introduction of more than 30 wt% dyeing sludge pellets is not conducive to improving the performance of the product, because a large number of macropores with size larger than 100 μm will be generated, which destroys the uniform and dense structure of the product. To ensure product quality meet the standard, the maximum dosage of dyeing sludge with pelleting is controlled below 30 wt%. This study provides an advanced method to improve the treatment efficiency of solid waste and the quality of products. [ABSTRACT FROM AUTHOR]

• The presence of salts influenced negatively properties of fired brick. • Desalination is required for the reuse of fly ash in brick production. • Chemically bonding forms of heavy metals changed after firing. • Leaching of heavy metals below regulation standards. The introduction of municipal solid waste incineration fly ash (MSWIF) during manufacturing process of fired bricks is a promising disposal method. However, the quality of products is negatively reduced and environmental risk increased significantly with the addition of MSWIF. This study proposed a novel approach to enhance the quality and environmental safety of fired brick by adding electric arc furnace slag (EAFS) as the pore plugger, which could overcome disadvantages brought by the introduction of MSWIF. Results showed that linear shrinkage and bulk density increased with the addition of EAFS, while water absorption and apparent porosity are reduced by more than 50%. The fracture microstructure of fired brick changed from porous to smooth with the addition of EAFS. The thermal conductivity declined by 25% and 30% at 1050 and 950 °C, and compressive strength was enhanced by 50% with the addition of 30 wt% EAFS. The chemically combination reactions between raw materials, such as the formation of albite, are promoted remarkably with the addition of EAFS. The leaching concentrations of heavy metals are far lower than regulatory limitations and environmental safety are enhanced significantly. In all, the addition of EAFS can promote the quality and environmental safety of fired brick, and can be used as an effective way to solve problems caused by introducing heavy metal solid waste. [ABSTRACT FROM AUTHOR]

Abstract To develop long-afterglow luminescent materials for white LEDs application, a series of Sr 1·97 MgSi 2 O 7-1.5x N x :0.01Eu2+,0.02Dy3+ (0 ≤ x ≤ 0.49) phosphors were designed. The single-phase samples were confirmed and the introduction of N was verified by the XRD patterns and energy-dispersive X-ray spectrum. The average particle size of the phosphors was determined to be about 4.9 μm. When the N is doped, it has been found the Eu2+ emission intensity decreases gradually, which could be owing to the increasing crystal defects by the nonequivalent substitution between N and O. The excitation spectra reveal that the broad and strong excitation bands from 240 to 450 nm can well match the LED chip. It is interesting that the incorporation of N can improve the afterglow time, which has been interpreted by the thermoluminescence curves. The investigation of the temperature-dependent luminescence indicates a beneficial effect on the thermal stability by doping N in the phosphors. Graphical abstract Image 1 Hightlights • A meaningful idea by combining LEDs and afterglow was proposed in lighting field. • The long afterglow time can be increased by introducing N in the phosphors. • The Sr 1·97 MgSi 2 O 7-1.5x N x :0.01Eu2+,0.02Dy3+ shows potential applications in w-LEDs. • The present results could be constructive to the development of similar phosphors. [ABSTRACT FROM AUTHOR]

Incineration is an alternative approach to disposal of tannery sludge due to the significant volume reduction. But the Cr(III) oxidation caused by Ca hydrates or carbonates in the incineration process could lead to incineration residue exceeding the required standard in the leaching toxicity of Cr(VI) and being listed in hazardous waste. A novel method of suppressing Cr(III) oxidation by introducing sulfates during the incineration of tannery sludge is proposed in this study. Cr(III) oxidation can be effectively inhibited with the introduction of NH 2 SO 3 H, NH 4 HSO 4 and NaHSO 4 at n (S)/ n (Ca) over 1.2. The combination reaction of sulfates and CaO prevents the Cr(III) oxidation. The inhibition of Cr(III) oxidation by sulfates is the most effective at 700–900 °C because almost all Ca is incorporated into CaSO 4 phase. NH 2 SO 3 H and NH 4 HSO 4 perform better in inhibiting Cr(III) oxidation than NaHSO 4. The intermediate product of Cr 2 (SO 4) 3 , which is formed below 500 °C, would decompose into Cr 2 O 3 with the temperature of over 600 °C. However, part of Cr 2 O 3 is still oxidized into CaCrO 4 aroused by CaSO 4 at a temperature of over 900 °C. Kinetic study showed Cr(III) oxidation could be effectively suppressed even if the heating time extends to 2 h at 800 °C. Toxicity Characteristic Leaching Procedure showed that the leaching concentrations of Cr(VI) from incineration residues with the introduction of NH 2 SO 3 H and NH 4 HSO 4 at n (S)/ n (Ca) of over 1.2 satisfied the requirement, and resultant residues could not be classified as hazardous waste. Due to inhibiting Cr(III) oxidation with high efficiency at 700–900 °C, the introduction of sulfates can be considered as a potential approach to prevent Cr(VI) formation during the incineration of tannery sludge by fluidized bed incinerator. • Cr(III) oxidation are suppressed by sulfates during heating of tannery sludge. • Inhibiting Cr(III) oxidation is strongly determined by temperature. • NH 2 SO 3 H and NH 4 HSO 4 are more effective in hindering Cr(III) oxidation than NaHSO 4. • Cr(III) oxidation is suppressed with sintering time being extended to 2 h. • Incineration residues cannot be listed as hazardous waste with adding of sulfates. [ABSTRACT FROM AUTHOR]

Abstract A series of Yb3+-Er3+, Yb3+-Ho3+, and Yb3+-Tm3+ doped Ca 2 Gd 8 (SiO 4) 6 O 2 (CGS) phosphors were synthesized by solid-state reaction method, and their upconversion (UC) luminescence properties for temperature sensing were studied. Upon 980 nm excitation, the green and red emissions of Er3+ were observed, and the optimal Er3+ concentration was determined to be 3 mol%. For the CGS:10%Yb3+,yHo3+ phosphors, three emission peaks in the green, red and near-infrared region appear. It was found that the relative intensities of Ho3+ different emissions change with Ho3+ concentration, which has been explained by the cross-relaxation process. The strongest Tm3+ emission appeared at 790 nm, attributed to the 3H 4 -3H 6 transition. The optimal Tm3+ concentration was determined to be 0.5 mol%. The temperature sensing behavior was evaluated by employing the thermally-coupled or non-thermally coupled levels of Er3+, Ho3+ and Tm3+. The maximum sensitivities obtained are 3.71 × 10 − 3 and 1.12 K-1 for CGS:10%Yb3+,3%Er3+, 0.111 K-1 for CGS:10%Yb3+,3%Ho3+ and 3.3 × 10 − 4 K−1 for CGS:10%Yb3+,0.5%Tm3+, respectively. The high sensitivities indicate the present phosphors could have potential application in temperature sensing. Highlights • Different strategies for temperature sensing were introduced in the present phosphors. • The present phosphors show smooth particle surface that benefits the UC luminescence. • High sensor sensitivity has been obtained in the CGS:Yb3+-Er3+/Ho3+/Tm3+. • The present phosphors could have potential application in optical temperature sensors. [ABSTRACT FROM AUTHOR]

A new synthetic method for 2-arylindoles has been developed, the process through Suzuki coupling reaction of 3-bromoindoles with hindered boronic acid catalyzed by Pd(OAc) 2 /PCy 3 , and a series of 2-arylindoles have been synthesized in moderate to high yields. [ABSTRACT FROM AUTHOR]