scholarly journals The Utilization of Modified Chitosan from Shrimp Shell As Photodegradation of Pesticides Paraquat Dichloride

2021 ◽  
Vol 6 (3) ◽  
pp. 204-208
Author(s):  
Risfidian Mohadi ◽  
Neza Rahayu Palapa ◽  
Rudi Hartono ◽  
Nurlisa Hidayati ◽  
Rozirwan

In this study, the chitosan modification of shrimp shell has been made by impregnated the chitosan from shrimp shell with Ti/ZrO2 and ZrO2 to formed composite of chitosan-Ti/ZrO2 and chitosan-ZrO2. These composites were made by immobilization technique and characterized by FTIR and SEM-EDX. The chitosan-Ti/ZrO2 and chitosan-ZrO2 composite were used as a catalyst to degrade the pesticide paraquat dichloride in the presence of UV light (????= 257 nm). The photodegradation process of paraquat dichloride takes place under 10 watts UV light irradiation and was measured using spectrophotometer UV. The maximum degradation percentage of pesticide paraquat dichloride photodegradation by chitosan-Ti/ZrO2 and chitosan-ZrO2 composites are 61.97% and 57.97% within 30 minutes irradiation time.

2008 ◽  
Vol 8 (5) ◽  
pp. 2719-2723 ◽  
Author(s):  
E. Liu ◽  
K. S. Tan ◽  
H. I. Tan

This paper studies the nanotribological behavior of magnetic rigid disks dip-coated with ultra thin perfluoropolyether (PFPE) Z-Dol 4000 lubricant layers up to 4 nm thick prior to or after exposure to ultraviolet (UV) light irradiation. Lube bonding ratios (LBRs) of 43–91% were achieved by varying the UV irradiation time. The nanotribological and mechanical properties of the disks were measured with a nanotribometer under varying loading conditions. The effect of the LBR on the nanotribological behavior of the disks was also elucidated. We found that the lubricated disks after UV treatment performed better compared to the lubricated disks without UV treatment. The experimental results indicated that the LBR of about 50% could achieve the best contact-start–stop and flyability performances.


2020 ◽  
Vol 82 (4) ◽  
pp. 695-703
Author(s):  
Amel Ounnar ◽  
Abdelkrim Bouzaza ◽  
Lidia Favier ◽  
Fatiha Bentahar

Abstract The current work investigates the removal of two hazardous macrolide molecules, spiramycin and tylosin, by photodegradation under external UV-light irradiation conditions in a slurry photoreactor using titanium dioxide as a catalyst. The kinetics of degradation and effects of main process parameters such as catalyst dosage, initial macrolide concentration, light intensity and stirring rate on the degradation rate of pollutants have been examined in detail in order to obtain the optimum operational conditions. It was found that the process followed a pseudo first-order kinetics according to the Langmuir–Hinshelwood model. The optimum conditions for the degradation of spiramycin and tylosin were low compound concentration, 1 g L−1 of catalyst dosage, 100 W m−2 light intensity and 560 rpm stirring rate. Then, a maximum removal (more than 90%) was obtained after 300 min of irradiation time. Furthermore, results show that the selection of optimized operational parameters leads to satisfactory total organic carbon removal rate (up to 51%) and biochemical oxygen demand to chemical oxygen demand ratio (∼1) confirming the good potential of this technique to remove complex macrolides from aqueous solutions.


Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1622
Author(s):  
Xiao-Pin Guo ◽  
Peng Zang ◽  
Yong-Mei Li ◽  
Dong-Su Bi

2-methylisoborneol (2-MIB) is a common taste and odor compound caused by off-flavor secondary metabolites, which represents one of the greatest challenges for drinking water utilities worldwide. A TiO2-coated activated carbon (TiO2/PAC) has been synthesized using the sol-gel method. A new TiO2/PAC photocatalyst has been successfully employed in photodegradation of 2-MIB under UV light irradiation. In addition, the combined results of XRD, SEM-EDX, FTIR and UV-Vis suggested that the nano-TiO2 had been successfully loaded on the surface of PAC. Experimental results of 2-MIB removal indicated that the adsorption capacities of PAC for 2-MIB were higher than that of TiO2/PAC. However, in the natural organic matter (NOM) bearing water, the removal efficiency of 2-MIB by TiO2/PAC and PAC were 97.8% and 65.4%, respectively, under UV light irradiation. Moreover, it was shown that the presence of NOMs had a distinct effect on the removal of MIB by TiO2/PAC and PAC. In addition, a simplified equivalent background compound (SEBC) model could not only be used to describe the competitive adsorption of MIB and NOM, but also represent the photocatalytic process. In comparison to other related studies, there are a few novel composite photocatalysts that could efficiently and rapidly remove MIB by the combination of adsorption and photocatalysis.


2021 ◽  
Vol 553 ◽  
pp. 149535
Author(s):  
Elisa Moretti ◽  
Elti Cattaruzza ◽  
Cristina Flora ◽  
Aldo Talon ◽  
Eugenio Casini ◽  
...  

2021 ◽  
Author(s):  
Yumei Mao ◽  
Xuehua Dong ◽  
Yuandan Deng ◽  
Jing Li ◽  
Ling Huang ◽  
...  

Two new zinc phosphites were prepared using the amino acid alanine as structure-directing agent. They have tubular and ladder-like structures exhibiting blue fluorescence upon UV light irradiation. Notably, the tubular...


1996 ◽  
Vol 54 (4) ◽  
pp. 331-337 ◽  
Author(s):  
M.Perla Colombini ◽  
Fabio Di Francesco ◽  
Roger Fuoco

1997 ◽  
Vol 105 (1219) ◽  
pp. 272-274
Author(s):  
Yutaka TAKAHASHI ◽  
Shigeo KOTAKE ◽  
Toshihiko OHTA ◽  
Akihito MATSUMURO ◽  
Masafumi SENOO

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