Gang Chu,Wangmin Wang,Yang Dou,Wenxiu Qin,Da Tian,Youbin Si
Phosphorus (P)-rich chars produced by phosphoric-acid-assisted pyrolysis are promising carbonaceous remediation agents for soil pollution. Nevertheless, the potential of P species dissolution from P-rich chars has been ignored, and the impact of P dissolution on the sorption of hydrophobic compounds remains greatly unaddressed to date. Herein, the P species dissolution from wood-, cellulose-, and lignin-derived P-rich chars at 200–650 °C were investigated. P release capacity ranged from 0.2 to 0.3 mg·g −1 through cyclic dissolution and the maximum release capacity was 1.6 mg·g −1 through continuous dissolution. Enhanced P dissolution in soil experiment implies that P-rich char can be a potential P source. After P species dissolution, bisphenol A (BPA) sorption increased and carbamazepine (CBZ) sorption decreased onto P-rich chars. The enhanced π-π interaction facilitated BPA sorption, while the declined double charge-assisted H-bond ((±)CAHB) weakened CBZ sorption. Combined with DFT calculations, the binding energy (ΔE) supported the contrasting interfacial sorption processes. Apart from micropore-filling, the contribution of sorption mechanisms followed the sequence of (±)CAHB > π-π interaction > H-bonding. This work not only reveals that P-rich char can serve as a promising phosphatic fertilizer for soil improvement but also casts new light on the sorption mechanisms for hydrophobic compounds.
Nitrogen/phosphorus enriched biochars with enhanced porosity were prepared through a one-step pyrolysis of bamboo sawdust activated by guanidine phosphate (GP). The thermal decomposition of GP released alkaline gas and hydrogen proton to create more micropores in biochar matrix which were extended to be mesopores further. Nitrogenous/phosphorous moieties of GP were introduced into biochars efficiently via cross-linking with the carbon skeleton. GP-activated biochar pyrolyzed at 450 °C exhibited enriched surface functional groups (11.3 at.% for N, 4.1 at.% for P), resulting in high sorption capacities for aquatic Pb(II) (166.2 mg/g), Cu(II) (81.7 mg/g), and Cd(II) (60.3 mg/g). Pb(II) was passivated fast with the formation of minerals including Pb 5 (PO 4 ) 3 OH and Pb 5 (PO 4 ) 3 Cl. Cu(II) was strongly coordinated with the N-containing species especially pyridinic N. Cd(II) was also captured efficiently due to the chemical complexation, cation exchange and cation-π bonds. GP-activated biochars could be well-recycling used to capture these heavy metals. Regarding these, the activation of biomass residuals could be an efficient approach to functionalize the surface of biochars with enhanced porosity, which is great benefiting for the immobilization of heavy metals from contaminated water.
In this study, phosphorus enriched LiMgP 1+ x O 4 (0.00 ≤ x ≤ 0.04) ceramics were synthesized via the solid-state reaction route. The crystal and phase structure patterns were analyzed by the Rietveld refinement and Raman spectroscopy. The dielectric properties were obtained at both microwave and terahertz frequencies. Optimal microwave dielectric performance was obtained in LiMgP 1.01 O 4 , sintered at 875 °C for 4 h: ε r = 6.964, Q × f = 82,057 GHz, and τ f = −27.1 ppm/°C (at 15.361 GHz). Compared with the pure LiMgPO 4 ceramics sintered at 950 °C ( Q × f = 79,100 GHz and τ f = −55 ppm/°C), an appropriate amount of excessive P 5+ reduced the sintering temperature while improving the Q × f value and the thermal stability effectively. Within the terahertz frequency range of 0.2–1.2 THz, the ε r values were decreased to 5.40–6.65 while the tan δ values were ranged from 0.0039 to 0.1228. All experimental results suggested that the LiMgP 1+ x O 4 ceramics are promising for both microwave and terahertz frequency applications.
Jie Liu,Jinhong Ren,Yunmei Du,Xiao Chen,Mengmeng Wang,Yanru Liu,Lei Wang
It is a great challenge to induce the formation of the RuP 4 phase and realize the construction of a metal-rich phase/phosphorus-rich phase-ruthenium phosphide heterostructure by directional regulation of the proportion of P and metal atoms. The ultra-high conductivity of Ru 2 P and the excellent ability of V-doped RuP 4 to absorb/desorb H* are confirmed by density functional theory (DFT) calculations, which laid a theoretical foundation for the construction of a unique Ru 2 P/V-RuP 4 structure to accelerate HER reaction kinetics. This work innovatively uses the V-doping strategy to induce the formation of RuP 4 phase with high intrinsic activity, and finally construct V-Ru x P y nanosheets with rich Ru/Ru 2 P/V-RuP 4 heterostructures. Thanks to the rich Ru/Ru 2 P/V-RuP 4 heterostructure and the optimization of V dopants, the V-Ru x P y catalyst only needs 180 mV to obtain an industrial-grade current density of 1 A cm −2 . In summary, this work provides a new idea for the design and performance optimization of ruthenium-based catalysts.
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