Rice Straw and Rice Straw Ash for the Removal of Brilliant Green Dye from Wastewater

El-Chaghaby, Ghadir A.; Ramis, Eman S.; Ahmad, Abeer F.

doi:10.9734/ajacr/2018/v1i29633

Cited by 13 publications

(15 citation statements)

References 21 publications

(29 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All values of 1/n less than 1 in Table 2 indicated the favorable nature of adsorption of Cd(II) onto the four rice straw adsorbents 25 , and the adsorption capacity was only slightly suppressed at a lower initial concentration of Cd(II). This isotherm did not predict any saturation of Cd(II) by the adsorbent; thus, infinite surface coverage was predicted mathematically, indicating multilayer adsorption of Cd(II) on the surfaces of rice straw adsorbents 39 .…”

Section: Resultsmentioning

confidence: 96%

“…The SEM image of Sp in Fig. 1 (Sp) showed Sp had a granular structure with irregular plates and cracks on its coarse surface 6,25 . The SEM image of Sa in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Compared with Sp, Ms had more surface O–H groups and aliphatic groups (-CH 2 and -CH 3 ), but the proportions of these groups were lower in Sa and Sb. Both incineration and pyrolysis (Sa and Sb) could remove large amounts of cellulose and hemicellulose from Sp 6,25 through depolymerization and decomposition, correspondingly reducing the surface O-H and aliphatic groups. The peak at 1734 cm −1 was attributed to unionized C = O stretching of carboxylic acid, which was only observed in Sp.…”

Section: Resultsmentioning

confidence: 99%

“…For the Langmuir model, to determine whether the adsorption system was favorable or not, the isotherm was classified with the separation factor ( R L ), which was calculated with the following equation (Eq. (7)) 24,25 :…”

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Characterization and Interpretation of Cd (II) Adsorption by Different Modified Rice Straws under Contrasting Conditions

Wang

Yao

et al. 2019

Sci Rep

View full text Add to dashboard Cite

Rice straw can adsorb Cd(II) from wastewater, and modification of rice straw may improve its adsorption efficiency. The rice straw powder (Sp) from the direct pulverization of rice straw was used as the control, the rice straw ash (Sa), biochar (Sa), and modified rice straw (Ms) were prepared by ashing, pyrolysis and citric acid modification, respectively, and all of them were examined as adsorbents for Cd(II) in this study. Batch adsorption experiments were adopted to systematically compare the adsorption capacities of rice straw materials prepared with different modification methods for Cd(II) from aqueous solution under different levels of initial Cd(II) concentration (0–800 mg·L−1), temperature (298, 308, and 318 K), contact time (0–1440 min), pH value (2–10), and ionic strength (0–0.6 mol·L−1). The results indicated that the modification method affected the adsorption of Cd(II) by changing the specific surface area (SSA), Si content, surface morphology, and O-containing functional group of rice straw. Compared with Sp, Ms held more surface O–H, aliphatic and aromatic groups, while Sa had more phenolic, C–O (or C–O–C), and Si–O groups, and Sb held more C–O (or C–O–C) and Si–O groups; besides, Sa, Sb, and Ms had larger SSA than Sp. Adsorption capacity of the four adsorbents for Cd(II) increased and gradually became saturated with the increase in the initial Cd(II) concentration (0–800 mg·L−1). The adsorption capacity of Cd(II) was significantly higher at 318 K than 298 K and 308 K, regardless of the adsorbent type. Sa had the largest SSA (192.38 m2·g−1) and the largest adsorption capacity for Cd(II). When the initial Cd2+ concentration was at 800 mg·L−1, the Cd(II) adsorption amount reached as high as 68.7 mg·g−1 with Sa at 318 K. However, the SSA of Sp was only 1.83 m2·g−1, and it had the least adsorption capacity for Cd(II). Only the adsorption of Cd(II) upon Sb at 298 K was spontaneous, and surprisingly, all other adsorptions were nonspontaneous. These adsorptions were all chemical, and were favorable, exothermic and order-increasing processes. The pseudo-second-order model showed a strong fit to the kinetics of Cd(II) adsorption by the four adsorbents. The adsorption capacities of Cd(II) by the adsorbents were less at low pH, and all were enhanced with the increase of initial pH value (2–10) in the solution. The inhibiting effect on Cd(II) adsorption due to the increase in ionic strength was greater with Sa, Sb, and Ms than that under Sp. The rice straw ash prepared by ashing unexpectedly had greater adsorption capacity for Cd(II) than the biochar and citric acid modified rice straw. The optimum condition for Cd(II) adsorption was established as the temperature of 318 K, initial Cd(II) concentration of 800 mg·L−1, contact time of 240 min, and no Na(I) interference regardless of absorbent. In conclusion, rice straw ash shows the greatest potential of being applied to paddy fields for the remediation of Cd(II) pollution so as to reduce the risk of Cd(II) enrichment in rice grains and straws.

show abstract

Section: Resultsmentioning

confidence: 96%

“…The SEM image of Sp in Fig. 1 (Sp) showed Sp had a granular structure with irregular plates and cracks on its coarse surface 6,25 . The SEM image of Sa in Fig.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Characterization and Interpretation of Cd (II) Adsorption by Different Modified Rice Straws under Contrasting Conditions

Wang

Yao

et al. 2019

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Rice is One of the most important crops worldwide which represents the stable food for more than 50% of the world population (Van Nguyen et al, 2006). In Egypt, it is an important field crop (Elmoghazy and Elshenawy, 2018); however, the residual straw and husk signify a serious problem for the farmers (Ragab et al, 2018, Daiem et al, 2018and El-Chaghaby et al, 2018. Around three teragrams of these residues remain unutilized annually in Egypt (Abdelhady et al, 2014).…”

Section: Introductionmentioning

confidence: 99%