Phosphorus (P) and fluoride (F) contamination in natural and industrial waters poses a serious environmental challenge. Mixed iron (Fe) and manganese (Mn) oxide composites have emerged as highly effective adsorbents for the removal of these pollutants from water. However, studies on real water system applications and the design of multicharged polymer-supported systems remain limited. In this work, FeMn-mixed oxides functionalized with polyacrylic acid (as a negative charge donor) and chitosan (as a positive charge donor) were engineered and applied as efficient adsorbents for the selective removal of P and F ions from both laboratory-prepared and real water samples. The as-prepared material was comprehensively characterized before and after adsorption using advanced analytical techniques. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses confirmed that carbon, nitrogen, and oxygen functional groups, together with the active participation of Fe and Mn ions, played central roles in the adsorption process. Real water samples collected from the Peshawar District (Khyber Pakhtunkhwa, Pakistan) were tested, and batch adsorption experiments validated the high removal efficiency of the composites. The composite exhibited a specific surface area ranging from 27.4 m2 g−1 before adsorption to 20.4 m2 g−1 after dye adsorption. Batch adsorption experiments demonstrated maximum removal efficiencies of 95–99% for both dyes under optimal conditions (pH 2–10, 298 K). Overall, this study presents a robust composite-engineering strategy and highlights the practical potential of the developed material for real-world water purification, particularly in industrial applications.
AhmadM, JamalA, TangX-W, et al.Assessing potable water quality and identifying areas of waterborne diarrheal and fluorosis health risks using spatial interpolation in Peshawar, Pakistan. Water (Basel), 2020; 12(8):2163.
2.
AigbeUO, OnyanchaRB, UkhureborKE, et al.Removal of fluoride ions using a polypyrrole magnetic nanocomposite influenced by a rotating magnetic field. RSC Adv, 2019; 10(1):595–609.
3.
AkaniroIR, WangG, WangP, et al.pH-tuneable simultaneous and selective dye wastewater remediation with digestate-derived biochar: Adsorption behavior, mechanistic insights and potential application. Green Chem. Eng., 2025; 6(3):344–356; doi: 10.1016/j.gce.2024.07.001
4.
AlaqarbehM, KhaliliF, BouachrineM, et al.Synthesis, characterization and investigation of Cross-Linked Chitosan/(MnFe2O4) Nanocomposite Adsorption Potential to Extract U(VI) and Th(IV). Catalysts, 2022; 13(1):47.
5.
AlqarniLS, AlgethamiJS, El Kaim BillahR, et al.A novel chitosan-alginate@Fe/Mn mixed oxide nanocomposite for highly efficient removal of Cr(VI) from wastewater: Experiment and adsorption mechanism. Int. J. Biol. Macromol., 2024; 263(Pt 2):129989; doi: 10.1016/j.ijbiomac.2024.129989
6.
AzeezNR, SalihSS, KadhomM, et al.Enhanced termination of zinc and cadmium ions from wastewater employing plain and chitosan-modified mxenes: Synthesis, characterization, and adsorption performance. Green Chem. Eng, 2024; 5(3):339–347; doi: 10.1016/j.gce.2023.08.003
7.
BhattacharyaS, BarN, RajbansiB, et al.Adsorptive Elimination of Cu(II) from aqueous solution by Chitosan-nanoSiO2 Nanocomposite—Adsorption Study, MLR, and GA Modeling. Water Air Soil Pollut, 2021; 232(4):161; doi: 10.1007/s11270-021-05070-x
8.
BhattacharyaS, BarN, RajbansiB, et al.Adsorptive elimination of methylene blue dye from aqueous solution by chitosan-nSiO2 nanocomposite: Adsorption and desorption study, scale-up design, statistical, and genetic algorithm modeling. Env Prog and Sustain Energy, 2024a;43(2):e14282; doi: 10.1002/ep.14282
9.
BhattacharyaS, BarN, RajbansiB, et al.Chitosan-nTiO2 nanocomposite synthesis and its adsorptive removal capacity for methylene blue from its aqueous solution: Batch adsorption study and modeling. ChemistrySelect, 2024b;9(15):e202400903; doi: 10.1002/slct.202400903
10.
BhattacharyaS, BarN, RajbansiB, et al.Synthesis of chitosan-nTiO2 nanocomposite, application in adsorptive removal of Cu(II)—Adsorption and desorption study, mechanism, scale-up design, statistical, and genetic algorithm modeling. Applied Organom Chemis, 2023; 37(6):e7094; doi: 10.1002/aoc.7094
11.
Blanco-VargasA, Chacón-BuitragoMA, Quintero-DuqueMC, et al.Production of pine sawdust biochar supporting phosphate-solubilizing bacteria as an alternative bioinoculant in Allium cepa L., culture. Sci. Rep., 2022; 12(1):12815; doi: 10.1038/s41598-022-17106-1
12.
Civan ÇavuşoğluF, OzcelikG, BayazitSS. Comparative investigation of phosphate adsorption efficiencies of MOF-76 (Ce) and metal oxides derived from MOF-76 (Ce). Langmuir, 2024; 40(8):4255–4266.
13.
DaiZ, QinT, BaiC, et al.Simultaneous treatment of phosphorus and fluoride wastewater using acid-modified iron-loaded electrode capacitive deionization: Preparation and performance. Front. Environ. Sci., 2023; 10:1087231; doi: 10.3389/fenvs.2022.1087231
14.
EarnestI, NazirR, HamidA. Quality assessment of drinking water of Multan City, Pakistan in context with arsenic and fluoride and use of iron nanoparticle doped kitchen waste charcoal as a potential adsorbent for their combined removal. Appl Water Sci, 2021; 11(12):191; doi: 10.1007/s13201-021-01531-0
15.
EltaweilAS, El-MonaemEMA, Mohy-EldinMS, et al.Fabrication of attapulgite/magnetic aminated chitosan composite as efficient and reusable adsorbent for Cr(VI) ions. Sci. Rep., 2021; 11(1):16598; doi: 10.1038/s41598-021-96145-6
16.
HuangX, PengJ, ZhangG, et al.Treatment of reactive blue dye-contaminated water via activated carbon adsorption and electrochemical degradation. Environ. Eng. Sci, 2025; 42(9):391–400; doi: 10.1089/ees.2025.0022
17.
HuangX, ShengX, GuoY, et al.Rice straw derived adsorbent for fast and efficient phosphate elimination from aqueous solution. Ind. Crops Prod, 2022; 184:115105; doi: 10.1016/j.indcrop.2022.115105
18.
JanaS, BhuniaK. Malachite green degradation by photocatalysis: Kinetics and mechanism using sol–gel synthesized nano-Titania. Environ. Eng. Sci, 2025; 42(8):340–353; doi: 10.1089/ees.2024.0381
19.
KhanA, ArifM, HanZ, et al.Mechanism and performances of methyl orange and Congo red adsorption by MnO2–PVP composite. Water Pract. Technol, 2024; 19(3):1047–1060.
20.
KhanA, NaeemA, MahmoodT, et al.Fixed‐bed column adsorption of methyl orange by poly(vinyl pyrrolidone)‐functionalized manganese oxide. J of Chemical Tech & Biotech, 2022b;97(10):2898–2903.
21.
KhanA, NaeemA, MahmoodT, et al.Mechanistic study on methyl orange and congo red adsorption onto polyvinyl pyrrolidone modified magnesium oxide. Int. J. Environ. Sci. Technol., 2022a;19(4):2515–2528.
22.
KhanA, NaeemA, MahmoodT. Kinetic studies of methyl orange and Congo red adsorption and photocatalytic degradation onto PVP-functionalized ZnO. Kinet Catal, 2020; 61(5):730–739.
23.
LiG, WangZ, LiuY, et al.Study on the adsorption mechanism and response surface optimization of fluorine and phosphorus by the red clay in Guizhou. ACS Omega, 2025; 10(15):15292–15308.
24.
LianSH, ZhangSN, LiuF, et al.[Phosphorus adsorption characteristics of different biochar types and its influencing factors]. Huan Jing Ke Xue, 2022; 43(7):3692–3698; doi: 10.13227/j.hjkx.202109156
25.
LiangL, HeJ, ZhouQ, et al.Enhanced adsorption of phosphate by rice straw-based biochar prepared via metal impregnation and bio-template technology. Environ. Sci. Pollut. Res., 2024; 31(27):39177–39193; doi: 10.1007/s11356-024-33795-9
26.
LiuR, SongJ, ZhaoJ, et al.Novel MOF(Zr)–on–MOF(Ce/La) adsorbent for efficient fluoride and phosphate removal. Chem. Eng. J, 2024; 497:154780.
27.
LuY, WangH, LuY-Y, et al.In-situ synthesis of lanthanum-coated sludge biochar for advanced phosphorus adsorption. J Environ Manage, 2025; 373:123607.
28.
LuoB, LiuY, YanY, et al.Research on the removal of fluoride from low-concentration fluorine-containing industrial wastewater using adsorption methods. Biochem. Eng. J, 2025; 216:109668.
29.
MaH, HuangY, TangJ, et al.Enhanced fluoride removal via adsorption flotation based on La-MOF carrier morphology modulation strategy. Sep. Purif. Technol, 2025; 365:132652.
30.
MilovanovićŽ, LazarevićS, Janković-ČastvanI, et al.The removal of phosphate from aqueous solutions by sepiolite/ZrO2 Composites: Adsorption behavior and mechanism. Water (Basel), 2023; 15(13):2376.
31.
MinL, MaY, ZhangB, et al.Electrospinning Chitosan/Fe-mn nanofibrous composite for efficient and rapid removal of Arsenite from water. Toxics, 2024; 12(3):230; doi: 10.3390/toxics12030230
32.
NevesT, LopesCB, MastelaroVR, et al.Toxic metals removal by new membranes based on graphene oxide and a cationic Polymer: Influence of chemical and morphological aspects. Chem. Eng. J, 2024; 498:155496; doi: 10.1016/j.cej.2024.155496
33.
ÖzacarM, ŞengilİA. A kinetic study of metal complex dye sorption onto pine sawdust. Process Biochem, 2005; 40(2):565–572.
34.
PapesB, ShimabukuK, GarbowskiM, et al.Per- and Polyfluoroalkyl substances removal using carbonaceous adsorbents in a brackish water circular economy. Environ. Eng. Sci, 2025; 42(7):304–313; doi: 10.1089/ees.2025.0028
35.
PazokiH, AnbiaM. Kinetic and isotherm studies of Cr(VI) adsorption from aqueous media by using a synthetic chitosan-allophane nanocomposite. Sci. Rep., 2025; 15(1):11088.
36.
PengZ, ZhangT-Y, AiJ, et al.Effects of a composite phosphate corrosion inhibitor on corrosion behavior and water quality stability in drinking water distribution systems. Water Cycle, 2025; 6:506–515; doi: 10.1016/j.watcyc.2025.05.004
37.
PetersCA. Environmental engineering science: Taking on today’s environmental grand challenges. Environ. Eng. Sci, 2025; 42(9):363–369; doi: 10.1089/ees.2025.0130
38.
QiJ, ZhangG, LiH. Efficient removal of arsenic from water using a granular adsorbent: Fe–Mn binary oxide impregnated chitosan bead. Bioresour. Technol., 2015; 193:243–249.
39.
SaniT, Gómez-HortigüelaL, MayoralÁ, et al.Controlled growth of nano-hydroxyapatite on stilbite: Defluoridation performance. Microporous Mesoporous Mater, 2017; 254:86–95; doi: 10.1016/j.micromeso.2017.04.036
40.
SawangjangB, InduvesaP, WongruengA, et al.Evaluation of fluoride adsorption mechanism and capacity of different types of bone char. Int J Environ Res Public Health, 2021; 18(13):6878; doi: 10.3390/ijerph18136878
41.
SelenV, GülerÖ. Modeling of congo red adsorption onto multi-walled carbon nanotubes using response surface methodology: Kinetic, isotherm and thermodynamic studies. Arab J Sci Eng, 2021; 46(7):6579–6592.
42.
ShahidMK, KimJY, ChoiY-G. Synthesis of bone char from cattle bones and its application for fluoride removal from the contaminated water. Groundw. Sustain. Dev, 2019; 8:324–331; doi: 10.1016/j.gsd.2018.12.003
43.
ShajiE, SarathKV, SantoshM, et al.Fluoride contamination in groundwater: A global review of the status, processes, challenges, and remedial measures. Geosci. Front, 2024; 15(2):101734; doi: 10.1016/j.gsf.2023.101734
44.
SharmaA, ShivannaJM, AlodhaybAN, et al.Efficient cationic dye removal from water through Arachis hypogaea skin-derived carbon nanospheres: A rapid and sustainable approach. Nanoscale Adv., 2024; 6(12):3199–3210.
45.
ShenM, YuY, FanG, et al.The synthesis and characterization of monodispersed chitosan-coated Fe3O4 nanoparticles via a facile one-step solvothermal process for adsorption of bovine serum albumin. Nanoscale Res Lett, 2014; 9(1):296; doi: 10.1186/1556-276X-9-296
46.
TolkouAK, ManousiN, ZachariadisGA, et al.Recently developed adsorbing materials for fluoride removal from water and fluoride analytical determination techniques: A review. Sustainability, 2021; 13(13):7061.
47.
VillarsK, HuangY, LenhartJJ. Removal of the cyanotoxin microcystin-LR from drinking water using granular activated carbon. Environ. Eng. Sci, 2020; 37(9):585–595; doi: 10.1089/ees.2020.0017
48.
WangC, ZhouY, YuF, et al.Recovery of phosphate from aqueous solution by modified biochar with concentrated seawater and its potential application as fertilizer. J. Environ. Chem. Eng., 2024; 12(3):112646; doi: 10.1016/j.jece.2024.112646
49.
WangX, WangG, YanY, et al.Removal of Mn(VII) and total Mn from Mn(VII)-containing aqueous solution by multifunctional flocculant modified polyacrylamide. J. Taiwan Inst. Chem. Eng, 2026; 178:106370; doi: 10.1016/j.jtice.2025.106370
50.
YangA, FuY, HuangF. Enhanced phosphorus adsorption performance of ZnAl-LDO by fluorine-chlorine co-doping and synergistic mechanism exploration. Sci. Total Environ., 2024; 955:177102; doi: 10.1016/j.scitotenv.2024.177102
51.
YangB, LiuD, LuJ, et al.Phosphate uptake behavior and mechanism analysis of facilely synthesized nanocrystalline Zn-Fe layered double hydroxide with chloride intercalation. Surface & Interface Analysis, 2018; 50(3):378–392; doi: 10.1002/sia.6391
52.
YangH, ZhangH, LuJ, et al.Advanced magnetic adsorbents for enhanced phosphorus and fluoride removal from wastewater: Mechanistic insights and applications. Sep. Purif. Technol, 2025; 353:128195.
53.
YangN, LiH, YinT, et al.A new method to assay hypoxia-inducible factor-1 based on small molecule binding DNA. Anal Chim Acta, 2014; 838:31–36; doi: 10.1016/j.aca.2014.05.045
54.
ZhangJ, LuX, ShiC, et al.Unraveling the molecular interaction mechanism between graphene oxide and aromatic organic compounds with implications on wastewater treatment. Chem. Eng. J, 2019; 358:842–849.
55.
ZhangL, ShangW, GuM, et al.Ozonation and granular activated carbon adsorption for the removal of refractory organic matter and decolorization during wastewater tertiary treatment. Environ. Eng. Sci, 2023; 40(5):187–195; doi: 10.1089/ees.2022.0175
56.
ZhangX, XiongY, WangX, et al.MgO-modified biochar by modifying hydroxyl and amino groups for selective phosphate removal: Insight into phosphate selectivity adsorption mechanism through experimental and theoretical. Sci. Total Environ., 2024; 918:170571; doi: 10.1016/j.scitotenv.2024.170571
57.
ZhouQ, RenB, WeiY, et al.Efficient removal of fluoride from water: Adsorption performance of MgO-x adsorbents derived from Mg-MOF-74 and insights from DFT calculations. Sep. Purif. Technol, 2025; 352:128190.
