Layered double hydroxides are traditional positively charged inorganic materials generally considered as efficient and low-cost adsorbents for the removal of anionic organic molecules. In this study, we prepared a series of g-C3N4@NiCo LDH composites by loading 10-30 wt% of g-C3N4 onto the LDH through the electrostatic self-assembly method. The bare LDH and g-C3N4 loaded LDH composites were characterized by XRD, SEM-EDS, Zeta, DLS, and FTIR techniques. Results revealed that extra peak corresponds to g-C3N4 originating in the XRD patterns, distorted morphology of LDH, reduction in positive surface zeta potential, and enhancement in hydrodynamic size after loading of g-C3N4 affirmed the successful formation of the composite. The adsorption performance of as-modified LDH was evaluated by removing the most commonly used salicylic acid and methylene blue as anionic and cationic model pollutant, respectively, from aqueous solution. The adsorption mechanism for both the pollutants by as-synthesized samples follows Langmuir isotherm. The results demonstrated that the bare LDH exhibited maximum adsorption efficiency of 75.16mg/g and only 3.66mg/g for salicylic acid and methylene blue, respectively. With 30 wt% loading of g-C3N4, the adsorption capacity for methylene blue increased to 25.16mg/g almost 6-7 times higher than that of bare LDH. On the other hand, the opposite effect on adsorptive removal of salicylic acid was observed with increase in the wt% loading of g-C3N4. With 30 wt% loading of g-C3N4, the adsorption capacity for salicylic acid decreased to 38.37mg/g, almost half that of bare LDH. A possible mechanism has been proposed. The kinetics for adsorption of salicylic acid onto bare LDH obeys the second-order model aside from the methylene blue adsorption which follows first-order kinetics. On the other hand, the kinetics of adsorption for both the pollutants onto (10-30) CN- LDH composites follows second order kinetics.

g-C3N4@NiCo LDH Composite Adsorptive Removal Interactions Of Ionic Pollutants Electro-kinetic Studies Adsorption Isotherms Surface Charge Variation

Helbling DE, Curr. Opin. Biotechnol., 33, 142 (2015)
Ahmed MB, Zhou JL, Ngo HH, Guo W, Sci. Total Environ., 532, 112 (2015)
Zubair M, Daud M, McKay G, Shehzad F, Al-Harthi MA, Appl. Clay Sci., 143, 279 (2017)
Levchuk I, Marquez JJR, Sillanpaa M, Chemosphere, 192, 90 (2018)
Baliarsingh N, Parida KM, Pradhan GC, Ind. Eng. Chem. Res., 53(10), 3834 (2014)
Talaiekhozani A, Talaei MR, Rezania S, J. Environ. Chem. Eng., 5, 1828 (2017)
Shan R, Yan L, Yang Y, Yang K, Yu S, Yu H, Zhu B, Du B, J. Ind. Eng. Chem., 21, 561 (2015)
Couto CF, Lange LC, Amaral MCS, J. Water Process Eng., 226, 156 (2018)
Mohapatra L, Parida K, Satpathy M, J. Phys. Chem. C., 116, 7350 (2012)
Zhang G, Zhang X, Meng Y, Pan G, Ni Z, Xia S, Chem. Eng. J., 392, 123684 (2020)
Arrabito G, Bonasera A, Prestopino G, Orsini A, Mattoccia A, Martinelli E, Pignataro B, Medaglia PG, Crystals, 9, 361 (2019)
Baruah A, Mondal S, Sahoo L, Gautam UK, J. Solid State Chem., 280, 120963 (2019)
Zubair M, Jarrah N, Manzar MS, Al-Harthi M, Daud M, Mu’azu ND, Haladu SA, J. Mol. Liq., 230, 344 (2017)
Chakraborty P, Nagarajan R, Appl. Clay Sci., 118, 308 (2015)
Zheng YQ, Cheng B, You W, Yu JG, Ho WK, J. Hazard. Mater., 369, 214 (2019)
Long YI, Yu JG, Jiao FQ, Yang WJ, Trans. Nonferrous Met. Soc. China English Ed., 26, 2701 (2016).
Huang DL, Liu CH, Zhang C, Deng R, Wang RZ, Xue WJ, Luo H, Zeng GM, Zhang Q, Guo XY, Bioresour. Technol., 276, 127 (2019)
Jiang DB, Jing C, Yuan YS, Feng L, Liu XY, Dong F, Dong BQ, Zhang YX, J. Colloid Interface Sci., 540, 398 (2019)
Zhang B, Dong Z, Sun D, Wu T, Li Y, J. Ind. Eng. Chem., 49, 208 (2017)
Yang YL, Mao BD, Gong G, Li D, Liu YH, Cao WJ, Xing L, Zeng J, Shi WD, Yuan SQ, Int. J. Hydrog. Energy, 44(30), 15882 (2019)
Ou B, Wang J, Wu Y, Zhao S, Wang Z, Chem. Eng. J., 380, 122600 (2020)
Sun ZX, Wang HQ, Wu ZBA, Wang LZ, Catal. Today, 300, 160 (2018)
Chen X, Li Y, Li L, Appl. Surf. Sci., 508, 1 (2020)
Chen X, Zhang WW, Zhang LX, Feng LP, Wen JW, Yang JJ, Zhang CX, Jiang J, Wang H, Appl. Surf. Sci., 481, 1335 (2019)
Ezzeddine Z, Batonneau-Gener I, Pouilloux Y, Hamad H, J. Mol. Liq., 223, 763 (2016)
Reddy PMK, Verma P, Subrahmanyam C, J. Taiwan Inst. Chem. Eng., 58, 500 (2016)
Wang T, Liu X, Ma C, Liu Y, Dong H, Ma W, Liu Z, Wei M, Li C, Yan Y, J. Taiwan Inst. Chem. Eng., 693, 298 (2018)
Megala S, Sathish M, Harish S, Navaneethan M, Sohila S, Liang B, Ramesh R, Appl. Surf. Sci., 509, 144656 (2020)
Tonda S, Kumar S, Bhardwaj M, Yadav P, Ogale S, ACS Appl. Mater. Interfaces, 10, 2667 (2018)
Nayak S, Mohapatra L, Parida K, J. Mater. Chem. A, 3, 18622 (2015)
Li T, Li GH, Li LH, Liu L, Xu Y, Ding HY, Zhang T, ACS Appl. Mater. Interfaces, 8, 2562 (2016)
Hu HJ, Liu JY, Xu ZH, Zhang LY, Cheng B, Ho WK, Appl. Surf. Sci., 478, 981 (2019)
Xia SJ, Liu FX, Ni ZM, Xue JL, Qian PP, J. Colloid Interface Sci., 405, 195 (2013)
Peng Z, Xin Y, Dong X, Quan Z, Ceram. Int., 40, 2115 (2014)
Ao YH, Wang DD, Wang PF, Wang C, Hou J, Qian J, Mater. Res. Bull., 80, 23 (2016)
Wang P, Ng DHL, Zhou M, Li J, Appl. Clay Sci., 178, 105131 (2019)
Mahato BN, Krithiga T, Thangam MAM, Surf. Interfaces, 23, 100636 (2021)
Ouassif H, Moujahid EM, Lahkale R, Sadik R, Bouragba FZ, Sabbar EM, Diouri M, Surf. Interfaces, 18, 100401 (2020)
Lu L, Li J, Ng DHL, Yang P, Song P, Zuo M, J. Ind. Eng. Chem., 46, 315 (2017)
Langmuir I, J. Am. Chem. Soc., 40, 1361 (1918)
Chilukoti S, Thangavel T, Inorg. Chem. Commun., 100, 107 (2019)
Li B, Zhang Y, Zhou X, Liu Z, Liu Q, Li X, J. Alloy. Compd., 673, 265 (2016)
Zhou Y, Li J, Yang Y, Luo B, Zhang X, Fong E, Chu W, Huang K, J. Alloy. Compd., 788, 1029 (2019)
Li S, Yang Y, Huang S, He Z, Li C, Li D, Ke B, Lai C, Peng Q, Appl. Clay Sci., 188, 105414 (2020)
Kumar KV, Porkodi K, Chem. Eng. J., 148(1), 20 (2009)
Moaty SAA, Farghali AA, Moussa M, Khaled R, J. Taiwan Inst. Chem. Eng., 71, 441 (2017)
Zhou Z, Ouyang S, Li P, Shan L, Ma R, Zhang P, Appl. Clay Sci., 188, 105500 (2020)
Sirajudheen P, Karthikeyan P, Ramkumar K, Meenakshi S, J. Mol. Liq., 318, 114200 (2020)