Cyanobacterial and Microcystins

My reading

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds. (pdf 1)

D. J. Barrington1, A. Ghadouani1, and G. N. Ivey2:

This study investigated the use of hydrogen peroxide (H2O2) for the removal of cyanobacteria cyanotoxins from within waste stabilization ponds.

The H2O2 produce the Lysis of cyanobacteria. In turn releasing intracellular microcystins to the dissolved state.

Cyanobacteria and cyanotoxins inhibit the biological, physical and chemical treatment to the wastewater.

In order to eliminated the cyanobacteria and cyanotoxins the traditional methods used copper sulfate or others coagulants and flocculants.

The traditional methods may be not remove the cyanotoxins.

The H2O2 had shown that remove cyanobacteria and cyanotoxins, and it is more success when it is combine with other treatment.

The chemical inhibits photosynthetic activity in cyanobacteria by impairing electron transfer and oxygen evolution, with can lead to the inactivation of photosynthetic II and eventually cellular death.

H2O2 also forms hidroxil hydroperoxyl (The hydroperoxyl radical, also known as the perhydroxyl radical, is the protonated form of superoxide with the chemical formula HO2) radicals which destroyed the toxicity of cyanotoxins, such as microcystins.

It has been demonstrated that the Bacteria found in activated sludge effluent are able to degrade cyanotoxins, particurlary microcystins species.

In order to quantifity phytoplankton used spectrofluorometry (not all the phytoplankton are cyanobacteria) .

Microcystins is dissolved by H2O2 and other system I said that because when do not existin H2O2 the micrcystins is dissolved too. The most important ways by degradation microcystins is by bacterial that stay in the water.

Although H2O2 may be a short-term strategy for the removal of cyanobacteria and microcystins, processes within the WWTP which contribute to rapid cyanobacterial growth must also be assessed, so that re-establishment of the cyanobacterial colony does not occur soon after algicidal treatment. It is thus important to consider whether it would be beneficial to remove cyanobacteria and microcystins earlier in wastewater treatment, such that the following WSPs in the treatment train are not infected by a continuous inflow of cyanobacteria.

For more information reader the methos uded in this paper.

A review on modification methods to cellulose-based adsorbents to improve adsorption capacity (pdf 2)

Sanna Hokkanen a, Amit Bhatnagar b, Mika Sillanpa€a€ a

Modification noanocellulose show better capacity for removed ions material than modification non-nano forms.

It demonstrated that metal ion adsorption efficiency was proportional to the number of carboxylic acids introduced.

Further processing after esterification would give better properties for binding metals from aqueous solutions. The esterified cellulose is commonly treated with a saturated sodium bicarbonate solution because carboxylate functions have better chelating capacities than the carboxylic group.

Material

* biomass

* Succinic anhydride

* pyridine and acetic anhydride

* N,N0 -dimethylformamide (DMF)

* 1,3-Diisopropylcarbodiimide (DIC)

* triethylenetetramine

* CuSO4*5H2O

* Pb(NO3)2

* CdCl2 * 2.5H2O

* Grade quantitative filter paper (Cat. No. 1441-150)

* Pyridine was refluxed with NaOH lentils overnight and distilled.

* Dimethylformamide was treated with 4 A˚ molecular sieves (MERCK) overnight and distilled under reduced pressure.

Priper the raw material.

Read pag 2.2

Characterization of modified materials:

* Mass percent gain.

difference in weight

* Degree of amination.

back titration. Two 0.1000 g samples of MMSCB 3 and 5 were treated with 100.0 mL of an aqueous HCl standard solution (0.01 mol/L) in a 250-mL Erlenmeyer for 1 h under constant stirring. Soon after the suspensions were separated by single filtration and three aliquots (25.0 mL) of each obtained solution were titrated with aqueous NaOH standard solution (0.01 mol/L)

* FTIR analysis

spectrocope

* Elemental analysis

Perkin Elmer 2400 Series II CHNS/O Elemental Analyzer. Combustion and analysis of gases.

Removal of heavy metals from aqueous solutions by succinic anhydride modified mercerized (pdf 3)

nanocellulose Sanna Hokkanen ⇑ , Eveliina Repo 1 , Mika Sillanpää 1

Regeneration of the modified nanocellulose was accomplished using nitric acid and ultrasonic treatment.

Mercerization treatment as a way of increasing the fibers specific surface area and to make the hydroxyl groups of cellulose macromolecules more easily accessible for the modification with succinic anhydride (succinylation).

Material and methods:

2.1Materials:

*Microfibrillated cellulose (MFC)

*Stock solutions of 1000 mg/L were prepared by dissolving appropriate amounts of Zn(II), Ni(II), Cu(II), Co(II) and Cd(II) nitrate salts in deionized water.

*Adjustment of pH was accomplished using 0.1 M NaOH or 0.1 M HNO3.

2.2 Cellulose mercerization:

Microfibrillated cellulose (MFC) (30 g) was treated with 0.20 L of NaOH solution (20 wt.%) at room temperature at least 16 h with

...