[Phosphate Removal Using Rice Husk Biochars Modified with Lanthanum Hydroxide].

La-modified RHBCs (La-RHBCs) were fabricated by immobilizing La(OH)3 nanoparticles on mesoporous rice husk biochars (RHBCs) using a co-precipitation method. Specifically, the effects of the pore structure of the RHBCs, solution pH, and coexisting substances on phosphate adsorption by the La-RHBCs were studied. The results showed that the La loading of the La-RHBCs was positively correlated with the mesoporosity of the RHBCs. La-modified RHBCs with higher mesoporosity hosts showed faster adsorption rates and lower leaching of La during phosphate adsorption. The adsorption process could be described by a pseudo second-order kinetic model, and the reaction rate was controlled by intraparticle diffusion. The Langmuir isotherm model fitted the adsorption process better, and the theoretical maximum adsorption capacities were 41.22, 43.26, and 45.62 mg·g-1, respectively. The high P/La molar ratios of more than 1.5 indicated the high utilization efficiencies of the La in the La-immobilized RHBCs. Moreover, phosphate could be effectively removed by the La-modified RHBCs over a wide pH range of 3-9. The La-modified RHBCs also exhibited good adsorption selectivity towards phosphate in the presence of coexisting anions and humic acids. Phosphate adsorption by the La-RHBCs was enhanced in the presence of Ca2+, while it was inhibited in the presence of Mg2+.

Experimental demonstration of photonic entanglement collapse and revival.

We demonstrate the collapse and revival features of the entanglement dynamics of different polarization-entangled photon states in a non-Markovian environment. Using an all-optical experimental setup, we show that entanglement can be revived even after it suffers from sudden death. A maximally revived state is shown to violate a Bell's inequality with 4.1 standard deviations which verifies its quantum nature. The revival phenomenon observed in this experiment provides an intriguing perspective on entanglement dynamics.

Experimental characterization of entanglement dynamics in noisy channels.

We experimentally characterize the bipartite entanglement under one-sided open system dynamics and verify the recently formulated entanglement factorization law [Nature Phys. 4, 99 (2008)]. The one-sided open system dynamics is realized by implementing a phase damping and an amplitude decay channel, respectively, acting on one of the qubits, by an all-optical setup. Our results greatly simplify the characterization of entanglement dynamics and will play an important role in the construction of complex quantum networks.