Aluminum hydroxide was successfully loading on PG. The cost-effective and high adsorption capacity of Al–PG had widely potential utilization on phosphate removal.
This study is aimed to examine the removal of nitrogen from high strength slaughterhouse wastewater at 11 degreeC via partial nitrification followed by denitrification (PND), using the intermittently aerated sequencing batch reactor (IASBR) technology. The slaughterhouse wastewater contained chemical oxygen demand (COD) of 6068 mg/L, total nitrogen (TN) of 571 mg/L, total phosphorus (TP) of 51 mg/L and suspended solids of 1.8 g/L, on average. The laboratory-scale IASBR reactors had a working volume of 8 L and was operated at an average organic loading rate of 0.61 g COD/(L-d). At the cycle duration of 12 h, COD was efficiently removed under three aeration rates of 0.4, 0.6 and 0.8 L air/min. Among the three aeration rates, the optimum aeration rate was 0.6 L air/min with removals of COD, TN, and TP of 98%, 98%, and 96%, respectively. The treated wastewater met the Irish emission standards. The microbial community analysis by fluorescence in situ hybridization shows 12 +/- 0.4% of ammonium oxidizing bacteria, and 7.2 - 0.4% of nitrite oxidizing bacteria in the general bacteria (EUB) in the activated sludge at the aeration rate of 0.6 L air/min, leading to efficient partial nitrification. PND effectively removed nitrogen from slaughterhouse wastewater at 11degreeC, but PND efficiency was dependent on the aeration rate applied. PND efficiencies were up to 75.8%, 70.1% and only 25.4% at the aeration rates of 0.4, 0.6, and 0.8 L air/min.
Manganese (Mn) oxide is a ubiquitous metal oxide in sub-environments. The adsorption of Cd(II) on Mn oxide as function of adsorption time, pH, ionic strength, temperature, and initial Cd(II) concentration was investigated by batch techniques. The adsorption kinetics showed that the adsorption of Cd(II) on Mn oxide can be satisfactorily simulated by pseudo-second-order kinetic model with high correlation coefficients (R2 > 0.999). The adsorption of Cd(II) on Mn oxide significantly decreased with increasing ionic strength at pH < 5.0, whereas Cd(II) adsorption was independent of ionic strength at pH > 6.0, which indicated that outer-sphere and inner-sphere surface complexation dominated the adsorption of Cd(II) on Mn oxide at pH < 5.0 and pH > 6.0, respectively. The maximum adsorption capacity of Mn oxide for Cd(II) calculated from Langmuir model was 104.17 mg/g at pH 6.0 and 298 K. The thermodynamic parameters showed that the adsorption of Cd(II) on Mn oxide was an endothermic and spontaneous process. According to the results of surface complexation modeling, the adsorption of Cd(II) on Mn oxide can be satisfactorily simulated by ion exchange sites (X2Cd) at low pH and inner-sphere surface complexation sites (SOCd+ and (SO)2CdOH− species) at high pH conditions. The finding presented herein plays an important role in understanding the fate and transport of heavy metals at the water–mineral interface.
Strong oxidant intermediates and the formation of byproducts during the discharge/charge process are the main challenges in the degradation of lithium-oxygen batteries (LOBs). A facile approach to maintain the stability of the cathode catalyst and avoid the formation of byproducts is essential for the development of LOBs. Here, a sawdust-derived carbon catalyst is fabricated and subjected to surface phosphatization to suppress corrosion between carbon and electrolyte/products. This prevents the formation of byproducts from parasitic reactions and boosts the reaction kinetics of the carbon catalyst in LOBs. The doped P atoms will prior to substitute an N atom in pyrrolic-N sites to form graphitic PN sites, instead of the graphitic PC sites. Experimental and density functional theory calculations reveal that the graphitic PN sites can function as a reaction kinetics promoter for the formation/decomposition of discharge products. Moreover, the graphitic PN sites can also prevent the formation of byproduct Li 2 CO 3 from the corrosion of the carbon catalyst, despite its poor catalytic capability in LOBs. As a result, the sawdust-derived P-doped catalyst exhibits an enhanced specific capacity of ≈20 000 mAh g -1 and long cycle stability of 226 and 160 cycles at 200 and 500 mA g -1 , respectively.
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