[Coagulation performance and mechanism of Alb species in polyaluminum chloride in removing humic acid].

Alb species [Al12 AlO4 (OH)24(7+)] is multinuclear hydroxyl compound formed in PAC hydrolysis-polymerization process, with properties of small particle sizes, much positive charge, high aggregation degree and large molecular weight. Alb species was purified from PAC containing high concentration of Alb species using ethanol-acetone mixed precipitation method. The influence of dosage, pH and inorganic ions on humic acid removal from simulative water was studied by measuring zeta potential and UV254. The PDA output (FI curve) was analyzed and the relationship between the parameters (S1, S2, H1, H2) of FI curve and coagulation mechanism were studied at different Alb dosage and pH. When the dosage was 4.3 to 6.3 mg x L(-1) and pH was 3.0 to 6.0, the highest humic acid removal efficiency was obtained. The existence of NH4+, SiO3(2-) and H2PO(-) inhibits the coagulation performance. The results of coagulation kinetics and Zeta potential studies revealed that Alb acted mainly by charge neutralization as well as adsorption bridge building in water treatment.

[QTL analysis of the uppermost internode length in rice under different growing environments].

A mapping population of 98 backcross inbred lines ( BC1F12 and BC1F13 ), derived from a backcross of Nipponbare (japonica) / Kasalath (indica) // Nipponbare by the single seed descent methods, was employed to map quantitative trait loci (QTL) of the uppermost internode length in rice under different growing environments by composite interval mapping method. The results showed that 13 QTLs relating to the uppermost internode length were detected under three differ- ent growing environments, and these QTLs were located on chromosome 1, 2, 3, 5, 6, 8, 10 and 11, explained 3.97 -15.21% of observed phenotypic variance, respectively. The locus of qUIL-6 was detected in three growing environments, and qUIL-1a, qUIL-3a, qUIL-3b and qUIL-10a were detected in two growing environments, indicating that these QTLs were stable and little affected by the environment.