scholarly journals Effect of Hydrogen Ion Presence in Adsorbent and Solution to Enhance Phosphate Adsorption

2021 ◽  
Vol 11 (6) ◽  
pp. 2777
Author(s):  
Taehoon Kim ◽  
Byungryul An
Keyword(s):  
Hydrochloric Acid ◽  
Adsorption Mechanism ◽  
Ph Effect ◽  
Total Surface Area ◽  
Point Of Zero Charge ◽  
Phosphate Adsorption ◽  
Hydrogen Ions ◽  
Solution Ph ◽  
Initial Ph ◽  
Ph Range

In this paper, the effect of hydrogen ions on the adsorption onto granular activated carbon (GAC) with the inorganic contaminant phosphate, which exists as a form of four species depending on the solution pH, is investigated. Various batch isotherm and kinetic experiments were conducted in an initial pH 4 as an acid, a pH 7 as neutral, and a pH 9 solution as a base for the GAC conditioned with deionized water and hydrochloric acid, referred to as GAC and GACA, respectively. The physical properties, such as the total surface area, pore volume, pore size distribution, and weight of the element, obtained from Brunauer–Emmett–Teller (BET) and scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM–EDX) represent no significant differences. However, the hydrochloric acid (HCl) condition results in an alteration of the pH of the point of zero charge from 4.5 to 6.0. The optimized initial pH was determined as being acid for the GAC and as being neutral for the GACA. According to the Langmuir isotherm, the relatively high Qm was obtained as being acid for the GAC and clearly distinguishes the pH effect as being the base for the GACA. An attempt was made to assess the adsorption mechanism using the pseudo-first-order (PFO), the pseudo-second-order (PSO), and the intraparticle diffusion models. The higher R2 for the PSO in the entire pH range indicated that chemisorption was predominant for phosphate adsorption, and the pH did not change the adsorption mechanism. A prolonged Bed Volume (BV) for the GACA demonstrated that the hydrogen ions on the surface of the GAC enhanced phosphate adsorption.

scholarly journals Efficient capture of phosphate from aqueous solution using acid activated akadama clay and mechanisms analysis

2018 ◽  
Vol 78 (7) ◽  
pp. 1603-1614 ◽  
Author(s):  
Ying Wang ◽  
Hui He ◽  
Nan Zhang ◽  
Kazuya Shimizu ◽  
Zhongfang Lei ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ph Effect ◽  
Phosphate Removal ◽  
Phosphate Adsorption ◽  
Order Kinetic ◽  
Negative Effects ◽  
Initial Ph ◽  
Intra Particle Diffusion ◽  
Langmuir Isotherm Model ◽  
Ph Range

Abstract In this study, akadama clay, a kind of volcano ash, was activated with sulfuric acid and then evaluated for the adsorption of phosphate from aqueous solution via batch experiments. The effects of adsorbent dose, initial pH and coexisting anions on phosphate removal by natural akadama clay and acid-activated akadama clay were investigated. Based on the pH effect, the modified adsorbent could efficiently capture phosphate over a wider pH range of 3.00–6.00 than natural akadama clay. Competitive anions showed negative effects on the phosphate adsorption, especially citrate and carbonate. The adsorption process followed the pseudo-second-order kinetic equation and the intra-particle diffusion. Langmuir isotherm model was found to fit the data better than Freundlich model, and the maximum adsorption capacities of phosphate onto the natural akadama clay and acid-activated akadama clay were 5.88 and 9.19 mg/g, respectively. Furthermore, thermodynamic studies confirmed that the adsorption of acid-activated akadama clay was a spontaneous process. The mechanisms of phosphate adsorption on the clay could be ascribed to electrostatic attraction and ligand exchange. These results suggest that after modification, acid-activated akadama clay could be used as a promising adsorbent for phosphate removal from wastewater in real application and then further used as fertilizers.

Radiolysis of aqueous chloroform solutions

1970 ◽  
Vol 48 (2) ◽  
pp. 271-276 ◽  
Author(s):  
B. J. Rezansoff ◽  
K. J. McCallum ◽  
R. J. Woods
Keyword(s):  
Oxalic Acid ◽  
Formic Acid ◽  
Hydroxyl Radicals ◽  
Ph Effect ◽  
Hydrogen Ions ◽  
Γ Radiation ◽  
High Ph ◽  
Hydrated Electrons ◽  
Presence And Absence ◽  
Ph Range

Saturated aqueous chloroform solutions (0.07 M) with pH ranging from 0.8 to 12.6 have been irradiated with 60Co γ-radiation in the presence and absence of air. G(Cl− + ClO−) increases with increasing pH in the pH range 1–3 (aerated solutions) or 3–6 (deaerated solutions) and again at pH greater than 10.5. The variation in yield from aerated solutions in the region pH 1–3 is attributed to competition between chloroform and hydrogen ions for hydrated electrons. However, such competition cannot account for the pH effect observed in deaerated solutions between pH 3 and 6. Increased yields from both aerated and deaerated solutions at high pH are attributed to the formation of O− by reaction of hydroxyl radicals and hydroxide ions. Formic acid and oxalic acid have been identified as minor products when aerated chloroform solutions are irradiated.

Preparation of Persimmon Tannins Immobilized on Collagen Adsorbent and Research on its Adsorption to Cr(VI)

2013 ◽  
Vol 743-744 ◽  
pp. 523-530 ◽  
Author(s):  
Jian Cui ◽  
Zhong Min Wang ◽  
Feng Lei Liu ◽  
Pei Bang Dai ◽  
Ran Chen ◽  
...  
Keyword(s):  
Adsorption Mechanism ◽  
Ph Value ◽  
Effect Of Temperature ◽  
Major Influence ◽  
Initial Concentration ◽  
Adsorbent Dosage ◽  
Adsorption Data ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Ph Range

Persimmon tannins (PT) were immobilized on a matrix of collagen fiber by cross-linking of glutaraldehyde. The adsorption behaviours to Cr (VI) on PT were investigated including the effects of initial pH, initial concentration of Cr (VI), temperature, adsorbent dosage, adsorption kinetics and the recycling performance of PT adsorbents. The results showed that pH value had a major influence in adsorption. PT showed a strong adsorbability to Cr (VI) in the pH range of 1.0 to 3.0, whereas the effect of temperature on the adsorption was comparatively weaker. The adsorption equilibrium could be well described by Freundlich equation. PT adsorption efficiency of Cr (VI) reached 98.04% and the maximum equilibrium adsorption capacity of Cr (VI) was up to 49.01 mg/g at 303 K with a pH value of 2.0, 100 mg/L of initial concentration of Cr (VI) and 0.1g of adsorbent dosage. The adsorption data could be well fitted by pseudo-second-order rate model. PT adsorbents were characterized by FTIR and EDS. The analysis indicated that the adsorption mechanism was mainly contributed by redox adsorption.

Adsorption of Methylene Blue and Congo Red on Bentonite Modified with CaCO3

2017 ◽  
Vol 727 ◽  
pp. 853-858 ◽  
Author(s):  
Han Bing Zhang ◽  
Ning Hua Chen ◽  
Zhang Fa Tong ◽  
Qi Feng Liu ◽  
Yan Kui Tang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Adsorption Isotherms ◽  
Adsorption Kinetics ◽  
Congo Red ◽  
Phosphate Adsorption ◽  
Adsorption Effect ◽  
Adsorption Performance ◽  
Initial Ph ◽  
Removal Efficiencies ◽  
Ph Range

Both bentonite and CaCO3 are cheap and abundant superior regional non-metal ores in Guangxi province, so it is very meaningful to jointly exploit bentonite and CaCO3 for real applications. In this study, bentonite modified with CaCO3 (CCB) was prepared and its adsorption performance of Congo Red (CR) and Methylene Blue (MB) was evaluated by investigating the adsorption influencing effects of initial pH, SDBS and phosphate. Adsorption isotherms and adsorption kinetics models were also fitted to analysis the corresponding kinetic characteristics of CCB. The results show that CCB exhibited superior adsorption performance with the respective > 90% MB and CR removal within the initial pH range 2 ~ 10. To a certain extent, MB removal efficiencies by CCB can be increased with the addition of SDBS. On the other hand, CR adsorption on CCB was inhibited slightly in presence of SDBS. But as a whole, removal efficiencies of MB and CR by CCB were kept constant when SDBS co-existed. MB and CR adsorption on CCB decreased to some extent because of competitive adsorption effect when phosphate co-existed. It also demonstrated that CCB can remove phosphate at the same time with dyes. Adsorption models including adsorption isotherms adsorption kinetics indicated that MB and CR adsorption on CCB was a monolayer process, and the adsorption rate depended on both adsorbent and adsorbate. In summary, CCB is a promising adsorbent for dyes removal with many advantages such as simple preparation technology, excellent adsorption performance for anionic and cationic dyes, broad fitting pH range and SDBS resistance. Besides, it can remove dyes together with phosphate at the same time. Therefore, this study is very useful for the dyeing wastewater treatment and exploiting the resources of bentonite and CaCO3.

scholarly journals Reclamation of Cobalt and Copper from Single- and Co-contaminated Wastewater via Carbonate and Hydroxide Precipitation

2021 ◽  
Author(s):  
Khyle Glainmer Quiton ◽  
Ming-Chun Lu ◽  
Yao-Hui Huang
Keyword(s):  
Adsorption Mechanism ◽  
Wash Water ◽  
Carbonate Precipitation ◽  
Solution Ph ◽  
Electroplating Wastewater ◽  
Precipitation Efficiency ◽  
Water Plant ◽  
Metal Ratio ◽  
Ph Range ◽  
Contaminated Streams

Abstract Wastewater containing cobalt and copper comprised of plating wash water, plant wash water, and equipment cooling and wash water is generated in the electroplating industry. These metals can be detrimental to humans, animals, plants, and the environment. Thus, it is necessary to treat electroplating wastewater to remove these toxic metals. Carbonate and hydroxide precipitation were utilized for the removal of Co(II) and Cu(II) from synthetic electroplating wastewater by jar tests in this work. The effects of solution pH, precipitant-to-metal ratio, and type of precipitant on the precipitation efficiency of cobalt and copper from the single- and co-contaminated systems were investigated. Carbonate precipitation achieved higher removal efficiency for both target metals in the single- and co-contaminated wastewater streams. Furthermore, it can operate at relatively low pH range of about 7.0-8.0. Cobalt in both pollutant systems was almost completely removed at pH 10.0 using both precipitant systems. Copper was found to be easily removed which was possibly brought about by precipitation-adsorption mechanism. The extent of the co-removal of cobalt with copper is significantly pH dependent. The effect of precipitant-to-metal ratio for cobalt and copper treatment varied in single- and co-contaminated streams. Carbonate precipitation led to lower sludge density than that of hydroxide precipitation.

scholarly journals Study of phosphate removal from aqueous solution by zinc oxide

2015 ◽  
Vol 13 (3) ◽  
pp. 704-713 ◽  
Author(s):  
Zhen Luo ◽  
Suiyi Zhu ◽  
Zhongmou Liu ◽  
Jiancong Liu ◽  
Mingxin Huo ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Zinc Oxide ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Chloride Ions ◽  
Phosphate Removal ◽  
Point Of Zero Charge ◽  
Phosphate Adsorption ◽  
Solution Ph ◽  
Base Interaction

Zinc oxide (ZnO) was synthesized and used to investigate the mechanism of phosphate removal from aqueous solution. ZnO particles were characterized by X-ray diffraction, scanning electron microscope and Fourier transform infrared spectroscopy before and after adsorption. Batch experiments were carried out to investigate the kinetics, isotherms, effects of initial pH and co-existing anions. The adsorption process was rapid and equilibrium was almost reached within 150 min. The adsorption kinetics were described well by a pseudo-second-order equation, and the maximum phosphate adsorption capacity was 163.4 mg/g at 298 K and pH ∼6.2 ± 0.1. Thermodynamic analysis indicated the phosphate adsorption onto ZnO was endothermic and spontaneous. The point of zero charge of ZnO was around 8.4 according to the pH-drift method. Phosphate adsorption capacity reduced with the increasing initial solution pH values. The ligand exchange and Lewis acid-base interaction dominated the adsorption process in the lower and the higher pH range, respectively. Nitrate, sulfate and chloride ions had a negligible effect on phosphate removal, while carbonate displayed significant inhibition behavior.

scholarly journals Enhancing the Removal of Sb (III) from Water: A Fe3O4@HCO Composite Adsorbent Caged in Sodium Alginate Microbeads

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 44 ◽  
Author(s):  
Jun Zhang ◽  
Renjian Deng ◽  
Bozhi Ren ◽  
Mohammed Yaseen ◽  
Andrew Hursthouse
Keyword(s):  
Sodium Alginate ◽  
Large Scale ◽  
Diffusion Reaction ◽  
Order Kinetic ◽  
Solution Ph ◽  
Composite Adsorbent ◽  
Practical Applications ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Ph Range

To remove antimony (Sb) ions from water, a novel composite adsorbent was fabricated from ferriferous oxide and waste sludge from a chemical polishing process (Fe3O4@HCO) and encapsulated in sodium alginate (SAB). The SAB adsorbent performed well with 80%–96% removal of Sb (III) ions within a concentration range of 5–60 mg/L. The adsorption mechanism of Sb (III) was revealed to be the synergy of chemisorption (ion exchange) and physisorption (diffusion reaction). The adsorption isotherms and kinetics conformed to the Langmuir isotherm and the pesudo-second-order kinetic model. Both initial pH and temperature influenced the adsorption performance with no collapse of microbeads within solution pH range 3–7. Most importantly for practical applications, these microspheres can be separated and recovered from aqueous solution by a magnetic separation technology to facilitate large-scale treatment of antimony-containing wastewater.

Study on an effective industrial waste-based adsorbent for the adsorptive removal of phosphorus from wastewater: equilibrium and kinetics studies

2016 ◽  
Vol 73 (8) ◽  
pp. 1891-1900 ◽  
Author(s):  
Ruzhen Xie ◽  
Yao Chen ◽  
Ting Cheng ◽  
Yuguo Lai ◽  
Wenju Jiang ◽  
...  
Keyword(s):  
Industrial Waste ◽  
Phosphate Removal ◽  
Phosphate Adsorption ◽  
Order Kinetic ◽  
Solution Ph ◽  
Before And After ◽  
Equilibrium And Kinetics ◽  
Equilibrium Data ◽  
Intra Particle Diffusion ◽  
Ph Range

In this work, an effective adsorbent for removing phosphate from aqueous solution was developed from modifying industrial waste — lithium silica fume (LSF). The characterization of LSF before and after modification was investigated using an N2 adsorption–desorption technique (Brunauer–Emmett–Teller, BET), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Studies were conducted to investigate the effect of adsorbent dose, initial solution pH, contact time, phosphate concentration, and temperature on phosphate removal using this novel adsorbent. The specific surface area for modified LSF (LLSF) is 24.4024 m2/g, improved 69.8% compared with unmodified LSF. XRD result suggests that the lanthanum phosphate complex was formed on the surface of LLSF. The maximum phosphate adsorption capacity was 24.096 mg P/g for LLSF, and phosphate removal was favored in the pH range of 3–8. The kinetic data fitted pseudo-second-order kinetic equation, intra-particle diffusion was not the only rate controlling step. The adsorption isotherm results illustrated that the Langmuir model provided the best fit for the equilibrium data. The change in free energy (△G0), enthalpy (△H0) and entropy (△S0) revealed that the adsorption of phosphate on LLSF was spontaneous and endothermic. It was concluded that by modifying with lanthanum, LSF can be turned to be a highly efficient adsorbent in phosphate removal.

Effects of CO2on Spray Solution pH

1995 ◽  
Vol 9 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Michael P. Braverman ◽  
James L. Griffin
Keyword(s):  
Deionized Water ◽  
Bicarbonate Concentration ◽  
Solution Ph ◽  
Spray System ◽  
Spray Solution ◽  
Initial Ph ◽  
Recovery From Acidification ◽  
Rate Of Recovery ◽  
Ph Decrease ◽  
Ph Range

The pH of deionized water, initially adjusted to a pH of 6 to 9, all decreased to near pH 5 upon pressurization with CO2in a backpack spray system. When deionized water contained bicarbonate (NaHCO3or KHCO3) at 0 to 800 mg/L to buffer against a pH decrease from CO2pressurization the return to their initial pH was more rapid than deionized water alone regardless of bicarbonate source. Acidification of spray solution following CO2pressurization of 138, 276, or 414 kPa was similar and bicarbonate had a greater effect than spray pressure. Addition of acidifying buffer and bicarbonate to the solution resulted in an initial and post-CO2pressurization pH range of less than one pH unit. All spray solution pH levels returned to near their initial pH following depressurization, indicating that the pH decrease was not permanent. Rate of recovery from acidification with CO2increased with initial pH and bicarbonate concentration.

scholarly journals Parameter optimization and mechanism research of enhanced coagulation treatment for Yuquan River water

2020 ◽  
Vol 20 (3) ◽  
pp. 1072-1082
Author(s):  
Qianshu Sun ◽  
Shuang Zhao ◽  
Yubo Yan ◽  
Wenlin Jia ◽  
Weihua Yang
Keyword(s):  
River Water ◽  
Removal Rate ◽  
Coagulation System ◽  
Optimal Dosage ◽  
Solution Ph ◽  
Enhanced Coagulation ◽  
Coagulation Mechanism ◽  
Xuzhou City ◽  
Initial Ph ◽  
Ph Range

Abstract As one of the drinking water sources for Xuzhou city, Yuquan River has been polluted seriously in recent years. In this paper, enhanced coagulation technology was selected and various parameters (coagulant species, dosage, solution pH and coagulant aid species) were optimized for Yuquan River water treatment. Turbidity and UV254 removal rate were calculated to assess coagulation efficiencies, and meanwhile floc generation kinetics, zeta potential and scanning electron microscope (SEM) spectra were measured to study the coagulation mechanism. Results indicated that the coagulation effect of polyaluminium chloride (PAC) on Yuquan River water was better than that of aluminium sulphate (AS), and its optimal dosage was 20 mg/L. Flocs produced by PAC also exhibited larger size and faster growth velocity than those of AS. Moreover, the applicable initial pH range for Yuquan River was 6.0–9.0, and the optimal coagulation efficiency was observed at pH 7.0. When PAC or AS was selected as coagulant, the application of sodium alginate (SA) could improve turbidity and UV254 removal due to its adsorption bridging role. In addition, coagulation efficiency could be enhanced in an AS coagulation system when polyacrylamide (PAM) was dosed as coagulant aid.

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